This has been done repeatedly,but it's good to know people are continuing to experiment.
kyrotech.com
(Looks like they went out of business!)was the first company that I know of to put a refrigeration unit into a computer case. It wasn't cheap,but it worked well.
In any event, your main problems will be 1- Catastrophic failure of the cooling system, overheating, and CPU burnout, and 2-Condensation.
If you decide to Liquid cool your 'puter,look up articles at
overclockers.com,and
maximumpc.com,and anywhere else you can find info. on cooling.
The MaxPC link has an article on heatpipes.Excellent reading.
The way to eliminate condensation is to use closed-cell foam,on the liquid pipes inside your case, and around the CPU.You should even put some behind the Motherboard,behind the cpu,and be generous in your coverage area.You could silicone-glue the stuff on, but common silicone has acetic acid in it, a boo-boo where it comes to fine wire traces.It will corrode them, even eat them away over time.
So you need a non-acid form of silicone glue(I don't know where you'd get it)...or some non-conductive epoxy, or simple'crazy glue'.
A water block is placed on top of the CPU,use some Arctic II to glue that sucker on(Thermal Epoxy).Then you wanna make sure you insulate the whole deal with closed-cell foam.
This way, you'll not have any condensation problems.And make darn sure none of your pipes leak!
Silicone tubing is an excellent use for this application, along with a high-flow aquarium pump.You can make the stuff yourself, or buy it (ouch!!!) from
melcor.com.Good luck.