This has happened to me twice on 19 flights as an A+ elite. Based in ATL. I'll post my exact upgrades later, but my record is 10 UGs on those flights, although I had a 6 flight dry spell in there, which wasn't fun, but I usually travel 5/7 in the evenings, so planes are probably a little more full.

It first happened on ATL-MEM on the last flight on a Friday night. I asked the GA who already had my BP ready.
It later happened on SAT-ATL on a Sunday 2pm flight. I noticed it on the kiosk when I checked a bag at the airport, and the GA also had one for me when I boarded. Either way, it was a pleasant surprise.

Another thing I like is the kiosks in C concourse in ATL. Makes checking BC availability just prior to boarding very simple.

I will update this post as I fly.

Successes:
1. Most recent was ATL-MEM 6:20 dep on 6/11. I think BC went out full... they were asking for volunteers.
2. MEM-ATL 7PM Sunday 6/6. Again, can't recall if BC was full.
3. ATL-MEM 3:15 Saturday 5/29 Plane was overbooked, BC full but one seat was a non-status Y UG.
4. 4/7/10 ATLLGA 7pm Wednesday.
5. 4/4/10 SATATL 2pm Sunday. BC was pretty empty.. they comped an UG to a family I think, and there were still empties. (auto UG)
6. 3/29/10 ATLLAX 7pm Monday. I had a free UG from getting screwed out of one on another flight, so not sure if this one should count. BC Full, but I think an NRSA took the last one.
7. 3/27/10 ATLMEM 2:24p Saturday
8. 2/23/10 MEMATL 6am Monday
9. 2/5/10 ATL MEM 6pm Friday
10. 2/1/10 MEMATL 6am Monday (my first flight as an Elite!)
11. 7/8/10 ATLMDW 6pm Thursday. 1BC went out empty Semi auto upgrade. Back of the plane was full, and 2 hours before the flight, BC was too, but we checked the seat map at check in and when we asked about UGs at the gate, the GA had us on a list for upgrade. Had to print tickets because I was travelling with my girlfriend on separate PNRs so they didn't have us in adjacent seats.
12. 7/16/10 ATLDCA 8:42pm Friday. BC was almost totally empty 4 hrs before departure and the back was oversold. Auto upgraded.
13. 8/29/10 MEMATL 7PM Sunday. Had a confirmed UG on the 7am because of a complaint, but realized at T-36hrs that I'd booked the wrong flight. Got on the 7pm with my upgrade processed over an hour before the flight.
14. 9/12/10 mematl 7pm Sunday. walked up 40 minutes prior and zone 4 was boarding. GA told me there were seats available up front, so I waited and was upgraded. BC went out with 4 empties.
15. 9/14/10 ATLMEM 6:21pm Tuesday. Auto upgraded (got there late, asked if there were any upgrades, told there were not, when I tried to board, the BP from home didn't work because they'd already upgraded me. GA handed me my new BP and down the ramp I went!
16. 9/15/10 MEMATL 7:13pm Wednesday. Got there at T-35. Friendly GA said she'd already paged me for an upgrade. Need to travel mid week more often! 4 open in C.
17. 9/24/10 ATLRDU 8:45am Friday. GA said my fiancee and I had already been paged. C went out full.
18. 9/26/10 RDUATL 6:55pm Sunday Fiancee and I both upgraded 30 minutes before scheduled departure (2 hr delay)
19. 9/28/10 ATLMEM 6:21pm Tuesday. Printed BP at kiosk and had been upgraded. 6 empty in C.
20. 9/29/10 MEMATL 7:13pm Wednesday. UG'd at gate, went out with one empty. plane was reeeeally empty, ~40pax total.
21. 10/1/10 ATLMEM 6:21pm Friday. Left with 1 empty.
22. 10/3/10 MEMATL 713pm Sunday. Got last UG. Elite directly behind me at the gate was denied an UG.
23. 10/9/10 ATLRDU 845am Saturday. Flight was oversold but BC was empty 2 hours before departure.
24. 10/15/10 ATLMEM 910pm Thursday. 6 empties an hour before departure, UG'd at T-45. C went out full.
25. 10/25/10 MEMATL 7:13 pm Monday. 2 Empty
26. 11/4/10 ATLMEM 9:10 Thursday. Left with 4 empty and 3 NRSAs in front. UGd well before 40 minute window it was so empty. Back of the plane looked pretty sparse too.
27. 11/12/10 ATLCAK 8:50am Friday. C was full
28. 11/12/10 ATLMEM 6:15pm Friday C went out full
29. 12/3/10 ATLMEM 6:23pm Friday C was full with 3 FL employees upgraded last minute.
30. 12/6/10 MEMATL 7:17pm Friday. 8 Empty in C
31. 2/22/11 MEMATL 7am Tuesday C went out full, but when I asked, it seemed they at least had two seats as I was offered a window/aisle choice.
32. 3/10/11 ATLMEM 7pm Friday. UGed on request at T-40. Another elite received the last one, but there was at least one elite in coach, C was full.
33. 3/28/11 MEMATL 8pm Monday. 3 taken at T-1.5 hrs, 3 open in-flight.
34. 4/4/11 MEMATL 8pm Monday 7 open at T-1, went out with 4 open. I'm moving to MEM shortly so that will be my last of these for a while, sure has been fun though.
35. 5/12/11 ATLCLT 1020pm Thursday C went out full
36. 5/15/11 CLTATL 430pm Sunday C was full
37. 5/22/11 RDUATL 1040am Sunday Upgraded at Ticket Counter
38. 5/22/11 ATLMEM 1pm Sunday Got an upgrade but took a VDB
39. 6/14/11 ATLMEM 11pm Tuesday due to taking VDB on earlier flight, but likely would have gotten UG either way.
40. 9/2/11 MEMATL 8pm Friday Labor day weekend. C was full
41. 9/2/11 ATLRDU 11pm Friday C filled up with an emp nonrev taking the final seat
42. 9/5/11 ATLMEM C was full i think.
43. 9/17/11 MEMATL 10am Saturday UG with Mrs. Cooger72 4 empty
44. 9/17/11 ATLJAX 140PM Saturday UG with Mrs. Cooger 3 empty
45. 9/18/11 JAXATL 825pm Sunday Auto upgraded because they needed my seat. C full.
46. 9/18/11 ATLMEM 1020pm Sunday Same as #45
47. 9/24/11 MEMATL 7AM Saturday
48. 10/5/11 MEMATL 7am Wednesday
49. 10/6/11 ATLMEM 10pm Thursday Last seat taken by an EMP.
50. 3/15/12 MEMATL 7am Thursday. They gave me the last seat when i walked up at T-40. Back was mostly full
51. 4/6/12 ATLCLT 1230 PM Friday. Seatmap and reservation updated to reflect my upgrade without me asking
52. 4/8/12 CLTATL 210 pm Sunday
53. 4/8/12 ATLMEM 618 pm Sunday. Upgraded before we arrived at the gate.
54. 8/20/12 MEMATL 345 pm Monday. paid $25 for a same day seat on the earlier flight, but the put me right into the front. C and Y both went out full.
55. 8/21/12 ATLMCI 1020am Tuesday. several empty in C. Back was pretty empty too.
56. 8/22/12 MCIATL 515pm Wednesday. C checked in full, but magically the GA called me to the podium and had a boarding card with 2A on it for me.
57. 8/22/12 ATLMEM 1030pm Wednesday. C had several empties.
58. 8/25/12 MEMATL 6am Saturday. Didn't have to ask, several left open when the flight went out. Mrs. Cooger72 also upgraded.
59. 9/3/12 JAXATL 4PM Labor Day. Mrs. Cooger72 and I were 5th and 6th to check in, first on upgrade list for 3 seats.
60. 9/3/12 ATLMEM 6pm Labor Day Ditto #59
61. 9/30/12 ATLMEM 845am Sunday. Mrs. Cooger72 was on a separate PNR, and I'd been upgraded when we got to the gate, but she hadn't. GA allowed her to sit up front as well! 5 seats open at take off.
62. 11/29/12 MEMATL 6am Thursday. BC was full
63. 11/30/12 TPAATL 1:10PM Friday. BC full
64. 11/30/12 ATLMEM 4:57PM Friday. BC went out full. This one took being sort of pushy after being given the runaround, but I got it. Plane was full on all of 62-64.
65. 1/4/13 MEMATL 5:55 PM Friday Wife and I got the last two seats.
66. 1/6/13 ATLMEM 1:05 pm Sunday. BC went out with 5-6 open, total of 72 on board. Mrs Cooger72 and I both upgraded without asking more than an hour before takeoff.
67. 5/2/13 MEMATL 11AM Thursday
68. 5/5/13 ATLMEM 9PM Friday. Last seat appeard to be given to a deadheading FA. Upgraded before I landed on previous flight.
69. 6/24/13 DENATL 7AM Monday. Was pleasantly surprised to be comped this. Think the bookings via WN.com have cut down the eligible upgraders at least temporarily.
70. 6/24/13 ATLMEM 1230 Monday. Was upgraded while on first flight, but had misconnected by landing.

Failblog:
1. 5/16/10 MEMATL 7pm Sunday
2. 5/14/10 ATLMEM 9PM Friday
3. 5/2/10 MDWATL 630 Sunday
4. 4/30/10 ATLMKE Noon Friday
5. 4/25/10 MEMATL 7pm Sunday
6. 4/23/10 ATLMEM 6pm Friday
7. 3/29/10 MEMATL 6am Monday
8. 2/19/10 ATLMEM 6pm Friday. I was flying standby and the GA said there might be space and to ask an FA. FA said I needed to get UG from GA, and UG'd a uniformed pilot despite my protest that I was elite. This is how i got my free UG for ATLLAX. A good trade/result from Customer service, but still a bad experience trying to UG on standby. (in fairness to the GA, I was running a little late and had miss the first calling of my name for standby boarding.)
9. 2/7/10 MEMATL 7pm Sunday.
10. 7/12/10 MDWATL 6am Monday. I was travelling with my girlfriend and the seatmap and GA said BC were full 1 hour prior to flight, but the seatmap showed a BC opening at last minute (after we were on board) and Y pax was UG'd. Wouldn't have helped us anyway as we needed two. Might be worth looking into how often that happens and whether it's worth waiting til the last minute to board.
11. 7/18/10 DCAATL 7pm Sunday. No upgrade despite a seat being available (and empty on the flight... 2 GAs told me separately that BC was full, despite the seatmap accurately saying to the contrary). I wasn't too concerned as I was travelling w/ gf, but I complained to CS via website and have been UGed early for my next flight.
12 9/10/10 ATLMEM 621PM Friday. One remaining seat was sold to a pax of size in front of me at T-30 minutes. Simply got to the gate too late.
13. 10/10/10 RDUATL 655 PM Sunday.
14. 10/17/10 MEMATL 713 PM Sunday. All seats filled 1hr + before takeoff.
14.5 10/21/10 ATLMEM 6:19pm Thursday Missed an upgrade, but i was flying standby and was the last one on the plane, so I don't think this one counts.
15. 11/8/10 MEMATL 707pm. Last UG given away/purchased while i walked from counter to gate. If I'd been there at T-40, would have gotten it. (Monday)
16. 11/12/10 CAKATL 3:33 pm full an hour+ before flight (Friday)
17. 11/14/10 MEMATL 7:07 pm (sunday)
18. 11/18/10 ATLMEM 6pm Thursday. the 9pm went out with 4 open in C but BC checked in full on the earlier flight.
19. 11/30/10 MEMATL Tuesday 7am Somehow 3 pilots trumped a revenue pax
20. 3/6/11 MEMATL Sunday 7pm. Full flight.
21. 3/14/11 MEMATL Monday 8pm. C was full by T-1hr, back was pretty empty.
22. 3/24/11 ATLMEM Thursday 7pm.
23. 5/12/11 MEMATL Thursday 7pm
24. 5/15/11 ATLMEM Sunday 624pm One seat was available, but needed 2 as was traveling with Mrs. Cooger
25. 5/19/11 MEMATL Thursday 7pm
26. 5/19/11 ATLRDU Thursday 1020pm
27. 5/22/11 ATLMEM Sunday 6:24pm Was bumped to this flight, and then bumped off of it, but there were no upgrades available.
28. 6/13/11 MEMATL Monday 215pm Last UG sold as mine was being processed. Flight was oversold but GA had enough volunteers (1 i think)
29. 6/13/11 ATLPIT 630pm Very few available that morning
30. 6/14/11 PITATL 2pm Very few available around 7am
31. 6/14/11 ATLMEM 7pm Tuesday Flight filled up during the day. Was over sold an hour before, and volunteered to take the 11pm, on which I got a confirmed upgrade at the time of VDB due to how empty it was.
32. 9/5/11 RDUATL 448pm Labor day. 2 seats when we checked in at counter had been sold by the time we got to gate.
33. 9/25/11 ATLMEM 623PM Sunday. GA appeared to screw us out of seats. Got comped UGs for later after submitting a complaint.
34. 4/6/12 MEMATL 7am Friday. BC checked in full
35. 9/29/12 MEMATL 6am Saturday. Was 1st to check in, and 2 seats were available at T-40, but the GA was doing other things, and one of them was sold while I waited. Since I was with Mrs. Cooger72, I turned down the single upgrade. Not sure if this should count as a success, but since we flew Y, I think it goes here.
36. 11/29/12 ATLTPA 9am Thursday. 2 remained at T-45 but they were sold before T-40 Womp womp.
37. 5/2/13 ATLMCI 330pm Thursday
38. 5/5/13 MCIATL 525pm Sunday
39. 6/24/13 ATLMEM 5PM Monday. Got bumped onto this flight due to missed connection. BC was full at that time.

Paid (credits):
1. 2/25/11 ATLLAS 10pm Friday. UGed at T-36 with 8 seats remaining, BC was sold out by T-24
2. 3/5/11 SFOATLMEM 1055pm Saturday. UGed at T-49 (6 remained at that time) will update on whether they sell out. Looks like this was a good call. Both flights ended up sold out in C, and at least one pax with an elite bag tag was in Y.
3. 8/30/12 MEMATLJAX Had an expiring comped upgrade.