I use the Zpacks Arc Blast. Which I am very satisfied with. I am not sure if it is advertised as 100% waterproof or not but after falling head first into the Big Sur river with it, nothing even became close to wet. The one thing that is worth mention though is I would not want to use it with a large bear canister inside, which for me is fine since I made a strap to carry the bear canister on the outside which obviously leaves you more capacity inside. At my heaviest on the JMT I had it weighed in at 40 pounds with water and 10 days of food.
