Just a stray thought, unless you are running a dp center or doing heavily numerical finite element analysis, do you really need all that computing power?
I'm writing this on a teeny 7" mid tablet and it doesn't even get warm. Arm/risc/linux/android-gingerbread.
Micellaneous Cooling Issues
We used to have thick copper buses on all boards to conduct heat away from chips because there's no convection in zero-g and the fans might fail.
I dimly recall reading of piped sulfur as a cooling medium. Don't try this at home.
Coolth may best be found in your dungeon and accessed by airflow through donkey dick or piped liquid through car radiators with fans. Biggest problem is trapping condensation.
Aerospace parts may have wider temperature specs but they tend to lag behind domestic parts.