Has anyone tried using corrugate plastic as a framesheet? It's bascially 1/4" plastic that resembles cardboard. I was thinking of using a 12"x24" sheet behind a lightweight 1/2" piece of foam padding.
I think it would be a good middle ground between stays and going frameless or just using a pad. I'm not sure how much it would weigh though. Also, you can't shape it very well, so it's up to the 1/2" foam to conform to your back. You might be able to get some large radiused, shallow curvature out of it though.

