Thanks HMS, good points. I guess I'm left with really building up the exterior, maybe even using the G10 plate you wrote about and bonding that to the outside or maybe some plywood/combination and then a lot of glass/epoxy to tie it all together. I am sold on vacuum bagging to in any event.
I hear you on the boat thing, and in retrospect, one would never look at a light fiberglass boat as an advantage. Fiberglass is one of the heaviest construction materials in the boat biz on a properly built hull. If I had it to do from scratch, I think the most elegant solution would be a traditional camper substructure with a Northern-Lite type cap. No free lunch.
