Although certainly not pocket sized, what about the good old Nalgene bottle? Waterproof...tough, see through. I've been mulling over the idea of what to put in quart size for a while now, but a pint size might yield good results as well. I've thought about individual kits for my family to keep in the car...easy to carry if we should have to abandon the car for some reason. Like so many of us who spend time re-working and re-thinking kits, it gives me something to do.

Speaking of which, I'm going to check out some of those Elkay bags...looks pretty handy.