Good luck in finding one. A canoeing dry bag with shoulder straps might work. I've given up on the idea of a waterproof pack. Too many openings and zippers for our rain forest. As you know, a functional substitute is to stuff anything that needs to stay dry inside a plastic bag inside the pack. When I want extra insurance a plastic sack inside a stuff sack works well, with the outer nylon protecting the plastic bag from puncture.
