Ramil Tranquilino is the first Im aware of in the enthusiast field
using Fluorinert with LN2 back in June of 2000 (there where later experiments)
http://www.octools.com/index.cgi?cal...ubmersion.html
of course Cray was pumping around and immersion and spray cooling almost from the beginning
http://ed-thelen.org/comp-hist/vs-cray-res.html#Cooling
thing about Fluorinert though is its not easy to seal against
for instance the Cray's employed welded stainless steel plumbing and "canned" pumps, its unlikely anything merely "water tight" will be Fluorinert tight
http://72.14.207.104/search?q=cache:...ient=firefox-a