Because of its fast evaporation rate, I wonder if it would be possible to make a self contained heatpipe, with an oversized rad at the top, and an air tight chamber under vacuum in which the computer is placed.
Look of flourinert (sp?) It's a flourocarbon which is very similar to this stuff, and also similar in costing a few hundred per gallon. It's beautiful material, used in submersion supercomputers, I always wanted to build a submersion PC with the stuff, however, you have the issue that if you were to pour a gallon out of a third story window on a hot day, it would never reach the ground. You would constantly be refilling, and it would cost more than the computer very quickly.