I can't stress enough how useful a rigged computer power supply can be. I ran 7 converters off one of them with no trouble. Of coarse I also can't stress enough how important it is to do it safely (ie check that you have the right cable and you have a sufficient load). You can virtually (I wouldn't try the motors) test your entire electrical system on one. note I make no claim that doing this is not without risk and if you do do it I don't guarantee that you won't fry some electronics. I never have, but it can happen. Here's a thread on how to rig one
http://www.chiefdelphi.com/forums/sh...ad.php?t=39754