I have an untouched 9m roll of aluminized, uncolored cuben that I probably won't find time to use. I believe it has the heavier mylar on one side (0.18 mil) and the lighter mylar on the other (0.08 mil). The product code is CT2K.18/KM.5 and it weighs 1.29 oz/square yard. I'm happy to send all or some of this to anyone who is interested in using it.
I don't want to make any profit (I like the idea of giving it away, actually), but it cost me about $25/yard if I remember correctly. So, I would probably want something like $18/yard for it. Shipping cost would depend on where you are and how you want it shipped (folded or rolled), I guess. My gmail address (email@example.com) is a better way to reach me than BPL PM.
UPDATE: A BPL member brought to my attention a recent thread about reflective cuben in commercial shelters like the Rocket Tent. Apparently, there have been problems with the material delaminating:
So, keep this risk in mind. For those who would accept the risk, there are two more yards available.
UPDATE 10/4/11: All of the material has now been spoken for.