I'm considering the same trip.
Darius has a nice write up (how I discovered this board actually):
http://millionmilesecrets.com/2012/1...ra/#more-17115
http://millionmilesecrets.com/2012/0...award-booking/
I live in LA, so anything besides LAX-PPT direct seems crazy. So basically I'm stuck with Air France (use miles on Delta), or ATN (AA miles). When I checked the seat availability for business/first basically Air France had 2 "award" seats period, while ATN only had 1. That means if you want to fly business on miles for a couple, you have to get some Air France miles or book through Delta (the delta forum had reports of problems getting first/business seats though - and I can't see any right now but I suck at this).
Anyway, that's 75,000 AA miles in coach, or 150,000 Delta miles in business on Air France. Honestly I'd just book AA Coach and call it a day since flying business is such a pain.