I've had this idea for some time, and reading how much you guys enjoy making your own gear I thought I'd throw the idea out there. How nice would a rain catch, small and light enough for backpacking be? Try to picture a circular-cut piece of one of the lightweight tarp fabrics such as silnylon. Hem the edge with a drawstring inside. Stich loops, maybe 1'' webbing, spaced around the perimeter. Now cinch the cord and tie off the loops to surrounding limbs, and you could wake up after an all night rainstorm to fresh water. It wouldn't need to be deep, more wide than deep. Just wide and deep enough to be sufficient. If anyone decides to make one some day let me know.