Demountable composite box to flatbed mounting system without pivoting subframe.

[rruff]

Part of frame twist is to keep wheels on the ground. If the frame did not twist, one wheel will be in the air and get no traction.

Yes, you'd need a better suspension system to compensate... or lockers.

 

[mud flap]

I manufacture insulated fiberglass truck utility bodies (which are sometimes used as a starting point for campers).

These trucks are DRW chassis cabs with C-channel frames and conventional flatbeds. Several of these trucks are used by rural fire departments, and are treated worse than a rental car by young men running "code three" to accidents, fires, etc and see lots of very rough use on poorly maintained fire service roads. The punishing use these trucks endure is much worse than most would want to subject their camper to, and the only structural damage any of them have picked up is from striking low hanging trees.