[redrooster]

The frame is reasonably thick. I haven't had any problems yet with my YJ frame swap and it is welded in many places.
After looking at your pics, you may be better off with the frame swap. I suspect that this may not be the only rust on your frame. It may be deteriorating from the inside and not made itself visible yet. You may want to knock around on it with a ball peen and see what else you come up with.
The major concern I would have with your particular frame swap is that the bolts all seem to be pretty rusty. You can anticipate most of them being pretty stubborn to remove. Lots of penetrant, a torch for heating and an impact will be required. Obviously you would want to replace all of the rusty bolts with some good grade 8's.
Google search shows Palmer Brothers Chrysler/Jeep in Birmingham, AL: 205-956-8861. When I bought mine, they had 4 others. All seemed to be in reasonable shape. I wire wheeled mine, painted it black and it was good to go. I would suggest a road trip rather than getting them to ship one. That way, you know what you are getting.