Sorry, no pics of it, but my uncle had an old truck with a camper shell, it was much like a utility top with hinged panels and windows along the sides. The bottom of the pannels had an alum. lip on the bottom loke an "L" that tipped up slightly on the bottom inside. You would open it like wings. A swing out post support at the front would swing back and you folded the bed down. He used an air mattres, I think something happened to the real mattress, it would lay down on top of those wings and the ply top went from side to side. He had a folding stool with a toilet seat and bags. He used a coleman stove and just his junk for hunting/fishing. Small wing pannels is the best way to explain it, noting really noteable for the 60s.
A neighbor had a top that had a bed that folded down along one side above the wheel well, but the top didn't do anything special.
That's a neat set up Prybry, looks like the old apache off the trailer and set on the truck. I almost bought a box tent trailer to do the same thing, but the door had to go to the sides and it would have opened the wrong way.