Thanks for all the responses! I've looked into a number of options but all things considered (especially simplicity, durability, carry options and $) I bought a 1L Lexan water bottle (to keep inside the backpack) and ordered a new 1qt GI canteen. The real deal straight from the source so it should be all right. If not, I'll be really mad. smile I'll also be getting a new thermos some time soon.