if I was crazy enough to try something like that I would start with a ground fault circut protecter (just in case) then I would find a computer recyler and get 2 or 3 old power supplies (the kind befor the atx ones, (they have a manual switch on them). The old supplies put out 5 volts at about 15 amps and 12 volts at abou 5 - 10 amps this will be much safer than house current and 2 should give you the current you need to power that many attys.
You can still use a ATX, just have to short out two pins on the mobo connector. (i.e. a Switch) I have used two to power a car stereo deck and a amp for my awesome back patio deck. got a 250w running the deck and 1000w running the amp.
Doing this in combo with what Scott said you might be on to something...
Im down to try it. 21 more lemmings to go.