I have dabbled in water cooling. Mainly with premade box kits. I had the Aquagate cooler that fits into two drive bays. Worked pretty good. Had a PCI interface to shut down your system if reservoir or block temps got too high.
When I first put it in, the default temp was like 30c. I booted, and within about 2 mins, the reservoir temp exceeded the default. This thing starts screaming and beepin, then shuts down. I was like wtf. I think agent was on the fone with me when it happened.
I want to get into a danger den setup, but just dont want to drop that kind of change into it. i have been thinking about a system where you run water in combination with a small refrigerator. Put the reservoir inside the coil freezer unit to chill things a lil. Not real phase change, but an extra chill.