some good ideas there BPJ. As for the ponchos, here is what the requirement actually says:
"Improvise a natural shelter. For the purpose of this demonstration, use techniques that have little negative impact on the environment. Spend a night in your shelter."
So,could one just find a rock shelter, make minor adjustments, and meet this requirement? I ask, because easily my best nights have been spent in natural shelters (better than even any nights in tents).