How about this:

• No hotel stay required
• Hope you can sleep on an airplane
• Hope you can sleep in a coach seat

Take Song FLL > LAX > FLL #2083 both ways on Wed Dec 7, 2005
#2083 leaves FLL at 7:00 am EST arrives LAX at 9:42 am PST (2342 MQMS)
Return on the same day
#2083 leaves LAX at 11:40 am PST arrives FLL at 7:42 pm EST (2342 MQMS)
Price after taxes: $258.40
MQMs earned: 4,684
$ Cost per MQM: 5.5 cents

You can repeat this same itinerary on Sat Dec 10 and Tues Dec 13

Of course it is 10 and 1/2 hours of flying each day; plus the 2 hour layover at LAX; plus the "hour-before-checkin" in FLL; for a total of 14 and 1/2 hours of your time invested with each day.

If you are trying for GOLD I would say go for it. If you are trying for Platinum I would say don't bother.

Another option would be to do a triangle of FLL > LAX > JFK > FLL
With this option you would need to stay overnight in Ft. Laud. Also, you would earn more MQMs per trip but the $/MQM ratio goes up
#2083 leaves FLL at 7:00 am EST arrives LAX at 9:42 am PST (2342 MQMS)
#2080 leaves LAX at 10:11 am PST arrives JFK at 6:28 pm EST (2475 MQMS)
#1984 leaves JFK at 8:15 pm EST arrives FLL at 11:15 pm EST (1069 MQMS)
Price after taxes: $336.10
MQMs earned: 5,886
$ Cost per MQM: 5.7 cents

A variation on the above would be to replace JFK with BOS (certain dates in December)
Again with this option you would need to stay overnight in Ft. Laud. You get more MQMs per run than the other two options. AND the $/MQM ratio decreases!
#2083 leaves FLL at 7:00 am EST arrives LAX at 9:42 am PST (2342 MQMS)
#2060 leaves LAX at 10:25 am PST arrives BOS at 6:49 pm EST (2611 MQMS)
#2075 leaves BOS at 7:55 pm EST arrives FLL at 11:21 pm EST (1237 MQMS)
Price after taxes: $327.60
MQMs earned: 6.190
$ Cost per MQM: 5.3 cents