After a lot of shop searching I've decided to give up on this idea. The prices seemed to be totaling around $6k for the van, $3k for the 4x4 donor van and $3k for the swap. $12k for a 1998 4x4 Savana isn't bad, but it isn't great either.

I have my back up plan, a 1979 Ford E250 Quigley 4x4. It's full of rust, but only $1200. I can enjoy it and gradually seek out someone that can do the body work (or a body swap?) for a reasonable price. If all else fails I can get my brother (@ $30/hr) to do it in a year when I move again.