Here they are (Yes, I know, it's old. Try taking a guess what this machine is...):
40MHz OC 68040 CPU (give or take 10W TDP, or 2A)
66MHz 486DX2 card (same I would say)
4x Molex (I don't quite understand how much these can carry, I've read reports that it can do more than 100W which seems ludicrous!)
1x Display card, not exactly a GPU as there is no acceleration. (max. 5V@2A, 12V@0.2A, -12V@0.2A)
4x Free slots (same specs as above), that may be filled later, so I need to provision for these.
Total would be 14W for the 5V rail (the most critical one), but that doesn't account for all the on board stuff or the molex powered devices...
That is about half what the VX550 can do, so I think this one would make a good and most importantly safe candidate, would'a think? Plus, I can get one under 50 bucks NIB.