Guys, it wouldn't be that hard at all... Unless I'm mistaken there are 2 wires that must be shorted out in order to power the PS. So link the ones from the "main" PS(one connected to the mobo) to the pins on the other one, and it would work...or I see no reason it wouldn't.
Hmm...maybe sometime I'll try this out if I get myself another ATX PS to play with. I only have one spare one ATM...