Another avenue which may put the seats in your hands would be the current Cash & Miles deal with Northwest. While I don't buy Cash & Miles myself (I'm wayyyyyy to addicted to miles to do it )... This might be perfect for your purposes. Often, there can be Cash & Miles seats available where there are no minimum level award seats:

http://www.nwa.com/features/Cash_Miles/domestic.shtml

Happy Contrails!