I'd also suggest that you look to see if there are any "referral" bonuses out there and sign up new users for FF accounts befores they fly. I know NWA has one of those out right now, and other airlines have in the past... although you wont get their "miles"... you'll get some bonus miles.

I'd also recommend the Citi Premier Pass Elite Card which wont give you "miles" but give you "Thank You" points for the miles that they fly when you buy their ticket... with hte 10K to 15K bonus point offers out there you'll be very close to the points you need for a free ticket using the Thank You Network.