WOW, mate, you're going hardcore! :cool:
It was suggested to me (the phase change cooling) when I started my TestBench thread... I did read about them, but somehow I still have reserves...
As I got it, they could be seen as freezers, at least they're working on that principle... most of those units are pretty noisy, so you have to consider where and when you're using them (I'm doing a lot of benching in night time, so it was an issue for me)...
Also, you have to keep in mind that everything below 0C most likely will cause condensations in your system... you can certainly insulate your mobo, but I'm not sure how that will go for 24/7 usage...
For myself I didn't felt that phase change cooling would be a good solution, but obviously there may be other opinions/experiences too... I'm sure that HiVizMan and 8 Pack have tried, so you may want their thoughts too...