couple ideas. first, most shower heads are just threaded on and can be taken off. put a T valve in that would normally couple to a hand held nozzle. then connect to this.
the second is to use an "intercooler" which is what i am planning on building. this gets the cooling water colder than the faucet water. use a resevoir (cooler, tub, etc,) filled with ice or ice packs. then pump water from this through the wart cooler and back over the ice. this has the effect of using colder cooling water and you need to use less water overall. you then don't need to have constant supply from the faucets