Have you thought about Tyvek.
Most of us just know it as the hard stuff used on buildings or in mailing envelopes but they make it in garment and foodsafe grades too.
Dupont even markets it in camo colours.

While I dislike the white housewrap with printing the cost is hard to beat.
You can soften it by running it through the laundry but other than painting it I don't know any easy way to change the colour.

A 10foot by 110 foot roll of tyvek housewrap seems to sell for about $120.00 (slightly over $1.00 a running foot).
You should be able to get some pretty cheap from a contractor.
They often end up with partial rolls.