I was reading the latest This Old House magazine, and came across a blurb for this:
http://www.rhythmboard.com/
When I see this sort of stuff, my mind always goes "How can something like this be used in the construction of my trailer?" If this is cheap enough, I might consider using it as a interior ceiling panel or even interior sidewalls. I'd suppose with a liberal soaking of epoxy, it might even hold up to exterior use. The "Gamma" series stuff has shallower flutes, which seems more suited to my intended use..