Good luck with that. I'm sure there's someone somewhere who will buy it.

Cuben is about it, for lighter than nylon waterproof fabric, but it's godawful expensive and perhaps not really what you'll want if the wind is blowing branches out of trees - nylon will rip too eventually but I've had branches and cones bounces off it.

Never seen water come through sil - I'm with those that theorize it's condensation and when rain hits the condensation bounces off.