Another interesting thought might be the use of a perfluorocarbon, which is a free-flowing liquid down to -100 degrees Celcius, non-toxic, and has tremendous heat-exhange properties--check out more information at the following address:

http://members.tripod.com/~Chemo_Gnostic/cryobio .htm

Also, for another similarly mad overclocking example, look at:

http://www.cpusite.examedia.nl/sections/steve/su percoolin.html