Heres a couple from Frozen CPU. The tough part about buying a phase change unit is finding a quality builder that creates units that perform above the norm. Spfoam1 picked up a single stage unit from a very talented phase builder. His single stage performs better or the same as a really good dice setup.
Unfortunately, right after he scored the unit, the builder turned into a jackfruit that was stiffing people on their orders and not returning phonecalls etc.
You can purchase a mass produced variant like one of the units here:
http://www.frozencpu.com/cat/l2/g41/...r_Express.html
but it may or may not be a good performer.
The company based in Tawain is branching out internationally, the shipping cost kill but their units may be worth the extra dough performance wise. Here is the website:
http://coolerexpress.com.tw/en-index.htm