If you know anyone with some technical know how, see if they can help identify what year Ford cars have the transmission that will work for you. Like I said, I've seen perfectly good transmission had for $75-100, just had to haul it home (or in your case to a place who can install it). There's probably tons of these laying around with low miles after the Cash 4 Clunkers program. All those big Ford vehicles getting their engines destroyed with perfectly good drivetrains.
Oh and whether you get a new, rebuilt, or junkyard tranny, you WILL have to replace the transmission cooler as there will be metal debris in it which will destroy anything you install.