I think that many people are successful with below ambient temp setups, you just have to be extra careful. I'll just tell you what I did, and my mistakes:
Conformal coated Everything, (protected the contact points (slots etc...) with tape, and then sprayed a generous amount of acrylic conformal coating. Look for MG chemicals website, they have dealer listings...
Rubatex (foam tape) on MOBO, Graphics card etc... all piping was wrapped.
My problem was the hose clamps, and the CPU bracket that holds on the water block... and the same for the Northbridge. When I do it again, I will fill those holes with Petroleum jelly, and just make that anything that might get cold, has rubatex on it.
And I think a real easy solution is to just make sort of "drip shrouds" so anywhere you might eventually have some leakage, you put like plastic cardboard to catch the run off (mine was near the hoses, so it wasn't hard to catch the run off, I just didnt' think of it then). you can actually get your board wet with the acrylic conformal coating, and it'll be just fine, you just need to make sure the condensation doesn't drip into any PCI/AGP slots. That's what happened to me, water dripped into the AGP slot, and shorted it, but only temporarily, I cleaned it out with a toothbrush and isopropyl alcohol, and it works just fine now.
Also remember, if you're refrigerating below freezing, the condensation will freeze... Jazzmon doesn't insulate at all, so his -50*C system just freezes anywhere... I think it's alot of work and preperation, but very possible, and I was more successful than I thought I'd be. As long as you have the right planning, you should be ok, I think there's quite a few people who have successfully done this. GL, Bill