Additional thought: clothing, tarps, and tents that were quiet in the rain would be a nice alternative.

The sound of rain on a hood, tarp roof, or tent can be nice but gets old after a while and it radically reduces your abiity to hear other things - sort of like an auditory version of looking into a light or fire reducing your night vision. It would be nice to have a choice of gear that eliminated the sharp, noisy pitter-patter for a quieter outdoor experience where you can hear the natural sounds around you - including that of rain hitting the landscape and wildlife adjusting to rain, etc..

I wonder how far off you can hear the sound of rain hitting a synthetic jacket, tarp, or tent? I'll bet it is a suprising distance. I can think of several situations where it would be nice to have the option to avoid announcing your presence throughout the neighborhood.