thanks to everyone for the kind words. regarding the pump and tank, I've definitely thought about putting a permanant tank on it, I really like the idea of those who've put them inside the frame rails. maybe if I can find the right tank. actually, a tank (or frame) with a expandable bladder might be even better, so it expands up to fill the entire area. anyway, maybe in a future revision.
Check for Tear Drop Trailer water tanks, they make them in very odd, flat sizes that could mount up perfectly between your frame rails and beneath the bed. I didn't find them until after I was done fabbing up the water tank in my trailer.
everything is working pretty well, but i'm a little disheartened by how quickly we're getting a little rust:
it's not really that bad, but, well, a disappointment. I've taken to storing it indoors. wondering if it has anything to do with galvanic corrision from having a battery grounded to the frame.
Don't let it bug you. Mine started to show a bit of rust pretty quickly too... just wait for your first good dent