cxfan1960: Not sure which of the older threads to put this in - the search threw up a few where this might be relevant, so please move this to the one that you think this post should be in.

Just redeemed 2x OneWorld Multi-carrier awards:

LAX-oLIM-EZE//GRU-xLIM-oLAX-oSFO-oLAX

115K miles + HKD 1140 in taxes pp for biz (last 2 legs, on AA in coach). Pretty good value imho, especially as 3 of the segments were overnight, so really wanted the business class seats.
GRU-LIM in biz opened up just today (pure luck, i was ok to redeem in coach when i tried doing the booking yesterday, based on what i saw as available from BA via KVS).

Attempt # 1 (yesterday): (mirroring percysmith's experience when trying to redeem an award on MH on 01 Feb)
Agent goes 'LAX-LIM is a codeshare flight, we cant book those'.
I insisted (friend's have booked this before, another agent was showing this option just last week, its OW marketed/operated blah blah) and the agent kept trying, putting me on hold.
No dice 20 minutes into the call and the agent (who had been profusely apologizing all the while for the delay) says 'having issues, could we please call you back). No call received in the 20 odd hours since.

Attempt #2: A few 'woahs'/E for England Z for zebra E for Englands/I see two flights - do you really want the overnight one (!)? etc, but no problem getting the LAX-LIM 'codeshare' that had been problematic yesterday, details double/triple checked and all good to go. Hope no issues at the ticketing stage.

Got to know later that this was the first OW award that the agent had booked (and she was thankful for me having done my homework), and we were working quite well togethar a few minutes into the call.
Total 38 minutes on the phone.
(I did press "1" to tell CX that I was satisfied with the call, though not sure if that counts for this helpful agent who did not dismiss anything i said/asked without trying first).

Now the interesting bit. I didn't really need the LAX-SFO-LAX leg, but added them
1) to make it a OneWorld award instead of an Asiamiles award (LAX-oLIM-EZE//GRU-xLIM-LAX would have cost 120K asiamiles)
2) since i could potentially use the LAX-SFO-LAX legs on a later date (since date changes are free), upto the ticket validity. (though might not be able to use after all, as i realized that award tickets are valid for 1y from the date of issue, not the first segment and these tickets are way into the future)

Also, the agent asked if GRU-xLIM-LAX with the first leg in biz and the second in coach was OK. This was the opposite of what I had expected(based on my stale info) 'maybe GRU-LIM in coach, and the overnight leg to LAX in business' and she volunteered to check GRU-LIM and LIM-LAX independently and got biz for both legs (the first one on a flight that had not been showing so far). Married segment logic (or reverse) in work here too...
Lesson to self: ask and check segment by segment as well as married segment (can't check GRU-xLIM-LAX availability via KVS).

Lastly -backtracking - we start in LAX, and stopover there once on the ticket (not booked as a transit), before moving on and coming back. This has been discussed before and a few posts mentioned that this is do-able, i can now confirm that it is. So in case anyone's searching for that, you can backtrack etc as long as you stick to the 5 stopovers, 2 transits, 2 open-jaws.
(no issues with/comments from the agent, except for an 'eehhhhh!!')

PS: I did not completley optimize the itin, as i could have snuck in a few intra-SouthAmerica legs (and kept just the smallest AA leg possible at the end to make it an oneworld award), but am happy enough given availability (in coach) was an issue for the intraSA legs and some of them would have made me hit the other constraints (like AEP-FTE taking up an Open Jaw as well as a stopover, precluding an open jaw at the end) - will just buy these using LAN's South America Airpass.