I got some of that woodland pattern sil-nylon 1.1 from LightHeart Gear. I made a 6'x10' tarp for my son that came in at 11.47 ounces with lines. I still need to seam seal it.
It is VERY waterproof in tests I did with the material prior to sewing it. This is some custom stuff they got made, and you can get it for $14.95 a yard here: http://www.lightheartgear.com/index....products_id=46
I found that it was about 1.53 ounces a yard for a finished project.