On Tue, 23 Oct 2007 18:14:12 -0400, HK wrote:

Any suggestions? Pitfalls?

Keep the tank reasonably small, 5 to 10 gallons is plenty for what you
describe. Water weighs 8 lbs to the gallon so excess capacity adds up
fast, and increases the structural loads on the mounting hardware. You
can use an inexpensive hand held shower head with an on/off push
button.