Ok, gotta be realistic here for a minute. The only viable market for expensive 7.25 stuff is early A body guys who are restoring their cars to the letter, and have no choice but to drop bucks if they want the part. The vast majority of the 7.25 market is guys who have later cars and CAN'T afford the upgrade to even an 8.25. You're gonna be hard pressed to milk any kind of cash out of those guys.
Think about it..$500 will get you an early B 8.75 with gears and a SG that will just about fall into an A body.