I've thought about doing that, but a pair of 60oz or so bladders in mypack, one on either side. If my top flap had a large enough map pocket, I'd put it there. <br><br>You might also check out Brigade Quartermasters or Ranger Joe's. They have an adaptor kit for GI canteens. It might be heavier than the bladders for the lighter systems, but the big ugly military jobs are also tougher. (Or at least seem to be.) Slip one of those into the side pocket, and you have a very cheap, very rugged, 1 qt hydration system that can stand on it's own. For a little more, you can go with the 2qt canteen. <br><br>Or you can buy a replacement hose with the bite valve, a Naglene bottle, some food- or medical-grade caulk, and play that route.