Here's the Caravan Campers frame, before being covered with lightweight sheet steel
I wonder if they would build a camper to the customer's specifications, say,
for use on a truck with a flatbed...or maybe for use in place of a flatbed.
That steel frame might be strong enough just to mount to the truck chassis!
You'd need a lot of insulation inside a steel box like this to stay comfortable.
Also, the painted steel skin of the camper would be very vulnerable to rust in
places where bushes scratch the finish. A fiberglass camper, in comparison,
has good insulating properties, and won't deteriorate much if the gelcoat is
scratched.
Chip Haven