Dale, I like your thinking.
Here's a couple of ideas to add.
White is likely too bright/reflective for your hiking buddies; think about beige/offwhite (may also need less processing in the recycle phase)
Vents- could these be rotatable, so they vent up in the dry (better ventilation) and rotate 180 so they're covered in the wet?
I'd prefer to drain to the back, since I would probably have a jacket on. Draining to the front means I'm continuously walking into a stream of water, straight down my venting zipper. (How about a tube/hole/port, that I can plug a Camelback hose into? No need to filter)
Maybe an adjustable, slightly elastic head band for better fit/comfort.
Sign me up for one of the first preproduction models!!