Although not camo, we have one of these tarps They are made with silicone impregnated nylon and are fairly water tight....as far as open shelters go that is. We use the tarp alot as it is so compact and light to carry in the backpacks. It serves well for not only keeping the wet elements off, but also the direct and hot summer sun while out in the more open areas when needed. It opens up to approx 7 x 8 feet.

This tarp is not cheap ($110.00 CA) but well worth it in terms of quality, convenience and very small size when folded and rolled down.

We bought the tarp last year and suspect we will get 5-6 years of regular use out of it so the ROI is good.