Just an idea, so don't flame!
I was looking over LN2/Dice cooling lately and I thought of a way to make it more convinient. When working with dice you normally will have a large copper "cup" with dice in it that sits on top of the CPU to cool it, of course there would also be neoprene/foam to prevent condensation from frying your motherboard.
So I was thinking, why not make use of copper heatpipe technology? I'm talking about something similar to the method that is used for fanless motherboard cooling. Except on the other end of the heatpipe is a copper cup with dry ice in it. This obviously will not have the same performance as a mousepot would, but with the proper design, the temperatures would still be sub ambient. And with heatpipes, they are much smaller and much easier to insulate with foam, etc. The dry ice would be outside your case which would even lower the chances of damaging your equipment.
Guys have any thoughts about this? And like I said before, this is not going to be as efficent but would still be cooler than water/air cooling.
G. Skill 4GB(2x2GB) DDR800
eVGA 8800GTS 320MB
super pi: 1m=20s