Something I use for prototyping, but also works pretty well for actual use, is "housewrap", as available from HomeDespot, or Lowies. There are two basic types:
First is the more expensive tyvek-based wrap. Runs about 170 bucks for a roll 150 feet long and 9 feet wide. My luck with this stuff has been limited. It tends to drum in a wind, is prone to tearing, but makes a wonderful vapor barrier. Stitching can be problematic until you get the machine setup right.
Then there is the less expensive poly wrap. This is a poly laminate with bilateral filaments very similar to tarp material. It is waterproof, vapor proof, easy to handle, and holds stitching well. Runs about 75 bucks a roll, same dimensions as above.
Suggestion: rather than make your first attempt out of expensive materials, use one of the above. Double stitch everything and use a fold-over welt. Put it together like you mean it and set it up. You may find it useable on the playa as long as you can make it close-fitting and maintain good abrasion control in your design (same as with any tent-type structure).