I've seen some of the swaps the guys with mid 50's trucks have done and some of the look pretty good.
To answer the above questions:
Yes the frame is narrow. The 50's guys have been using wheels adapters to get the wheels out farther.
I'm not worried about payload. In the 20+ years I've had the pickup, the heaviest thing I put in the back was a new washer from Sears. My old 3/4 ton Chevy van and trailer is used for any thing bigger than that.
I'm thinking on the lines of my cab and a small wooden stake-bed on the back; mounted on a mid 80's long bed S10 frame.
It won't be a show truck; I'm not into that type of stuff. Just an economical runaround truck or at least more economical than it is right now.
Here's a link to one of the 50's swaps.
http://67-72chevytrucks.com/vboard/s...d.php?t=305723