It will have to be well over 250w. I have a 226 pelt hooked up to a 320-15 Meanwell. Just for grins I put in on my i7 920 overclocked to 4.0ghz under a really good water cooling system. As I was told to expect it promptly was overwhelmed by the heat of the 920. I had my alarms set at 75c and they went off at about 2 minutes and temps were still climbing rapidly. Without TEC the same water cooling holds temps at 4.0 to about 70c fully stressed.
If Gabe can come up with something at ~400 watts I will go for it. Much less and I don't think it will be worth it.