Here is what my dad did to what is now my truck.
He had the wooden bed too, which rotted out by the 1980's.
He removed the wood (although it appears there is undercoated plywood underneath). He got a hold of 1/8 inch flat steel from the coal mine where he worked (they were pretty free with left-over materials) and he cut that to size and welded it onto the three bed sides and bottom.
He didn't weld to the truck frame, he bolted that in, removed the bolt heads,
plug welded the bolts to the new bed bottom, ground down the welds smooth, and painted everything.
My bed is seamless! *The welds look great!* Dad tells me the bed can be removed via jacks as "he's done it before, by himself," [after finishing the work.] So there is one option.
