Nah, the shell of a camper is just a shell. The shell really does not add anything structural to the frame. Ever see one crumpled up on the side of the highway (usually it's someone pulling a 28 footer with a sable). Any ways, if you can find a tandem axle "camper" frame, and are willing to do some work, you can come up with a real nice one. You will need to do some welding, wiring, cutting of wood and metal, etc.
If your not up to that, just get one like your looking at or similiar. I have been building a small one in my spare time from scraps, free parts, etc. I have about $75 bucks into it and many hours of cleaning old metal, cutting, grinding, welding, painting, etc. Almost done, BUT, just seen an ad at Harbor Frieght, a small utility trailer similiar to what I am building for about $100 more than what I have into mine so far. I wonder what my labor is worth. Probably more than that $100 bucks!
I admit, my welds are looking pretty good, after all I did get plenty of practice! Mine is probably built stronger than the HF one, but, better off just buying one unless you need a reason to spend time in the garage, get yourself all dirty, cut your hands, burn your legs with weld spatter, welders flash to the eyes, and get grinding dust all over everything in the garage. Can you tell I'm getting tired of this project? KD