I've been interested in both the NL 10-2 and BF 10.4, so are you saying that the structure of the fiberglass does not support itself? It requires being bonded to the polystyrene and interior paneling to support the structure of the camper?
I understand how strong stress skin panels are. I've worked on a few. I had a Palomino 8801 that was made that way. Very strong, but the glass was only 1/16" thick and it had an aluminum frame around the edge of each panel.
I thought that both BF and NL were made like a boat, which has a few frames and the transom glassed into the hull but most of the strength in the thickness of the molded fiberglass which is a factor of only fiberglass lamination.