Sean
There is such a liquid for submerging the entire board already, for some time now. It's a non conductive liquid of course, a type of oil or parafin or something, can't remember what it was exactly. I believe some german (I think) system buider sells such a setup, the case was quite nice I believe. You extracted the board from the top, with a handle, but problem is it usually was a mess if you had to do so to change a vid card or so. Cool though.