I'm building my '63 3/4 ton 4x4 now. I got a new body from a 2wd truck and was noticing the frame difference when I dismantled them. The 2wd has a more curvy frame designed to work with front independent suspension and rear coil springs. The 4x4 has a straight frame to accomodate the front and rear leaf spring suspension. I too looked at a frame swap since mine was rusted in a couple of spots, but there was no way I could make a 2wd 1/2 ton frame work with my drivetrain parts. If you stripped your frame down to nothing, I would think a good body shop could straighten it for you. You may want to look into a mid 70's frame as a possible donor too. Good luck saving it,
Scott