I was in the OR factory store this weekend and saw the DryComp Ridge Sack, which is a 16.4oz/465g, 34 liter roll-top waterproof backpack.
Looks like it has great potential for rainy season day hikes, water travel, UL overnights, etc.
It could be trimmed a bit, as it has ice axe loops and a full set of compression straps. It has a large mesh pocket on the back that could hold a water bladder-- too bad it doesn't have water bottle pockets.
List price seems a little spendy at $119, but I see that at least one on-line retailer has it at $85.
Has anyone tried one with a 20 pound load?