RB:

There is a website somewhere that shows plans for a very expedient slightly domed cover that can be made from any tarp or poncho and some fiberglas or aluminum tent poles. Very practical and easy to construct with an insulating ground cover the only thing necessary to supplement it. It is portable, wind resistant because of its design, and quick to assemble and disassemble.

Sorry I do not have the link to it.

Bountyhunter