I saw the traffic coming into the site from the forum and thought I'd stop in to say hi and answer any questions. Looks like you folks have a pretty firm grip on things :-)
Couple of things you might find useful.
discusses using materials other than the insulation boards including corrugated plastic (thin, light) and plywood (cheap, durable.) If you're handy, the plywood hexayurt has a lot of potential for cheap, occasional use buildings akin to mountain huts. Might be worthwhile for events where you've got a lot of people coming to a location, like motorcycle rallies or something (I'd say Sturgis but isn't that the other folks?)
The other thing is that the folding hexayurt might be the way to go for camping use like you envisage.
(that's the German army helping out at Operation Combined Endeavor, a US DoD sponsored communications festival in Germany. Lovely chaps, very good engineering!)
This one, for example, is 8' from corner to corner, 6' high in the center, and 7' wide. The biggest component is 2' x 4', which is a fairly packable size. You could do the entire wall as a single piece that size, and the roof as a single piece half that size (diagonal cut) and using some thin material like corrugated plastic with velcro.
I'm still not sure that's a motorcycle touring system but if you're hauling a small trailer, it would be fairly light, and I think the shelter would be pretty high quality even in fairly light materials particularly if you looked at laminating something reflective on the outside of the panels (mylar? aluminium foil?)
If anybody wants to take a crack at a project like that, I'm usually around to answer questions, though not always - [email protected]
, or join the mailing list (there's a sign up box on the main web site, http://hexayurt.com
Any questions I can answer? Anything I can do for you?