This is ridiculous. As long as it is getting power the Vapochill has no clue whether its source has 1 or 2 12V rails. I dont care if you are running a Vapochill setup, there is NO WAY it will draw more than 18A on a 12V rail...hell i would be suprised if it pulled more than 8A.
Take a look at the Seasonic, Tagan, Fortron, Antec, OCZ....
For single rail, Zippy is about the only one that still holds true to it. They are by far one of the best manufacturers. OCZ is an enthusiast brand PSU, Zippy is an INDUSTRIAL brand. There is no comparison (Same with PCP&C, you really cant compare them).
Once again, there is no reason to get a single rail PSU, for that setup I would probably look at the Seasonic S12 500Watt, or any nice fortron unit. You shouldn't need anywhere close to 500Watt for that setup so i wouldn't go wasting your money and getting a 600 Watt Behemoth.
-Kevin