I'm not as expert as the other members of the page, but I have blown up enough PSU's to tell you something:
I never heard about good results with parallel PSU. If you want more power, get a better PSU. If you want redundancy, you can get special PSU's with two AC jacks. If one AC source fails, the other is used inmediately.
I've heard about DIY modified PSU's used for car computers, giving from 12V the 12, 5, 3, 0, -5 and -12 used by the computer, but I don't really get how do they make the trick, I guess they remove the rectifiers, frecuency and step down circuit, and do some kind of black magic...
You can also buy the commercial version
Believe me, DIY is perfect for most cases, but on this application the smell of burnt oil is not good, the voltages of the game are dangerous, and I guess your equipment is too expensive to risk it
is your choice!