Look into thermoelectrics or phase change for 24/7 operation, not liquid nitrogen.
Overclockers are unlikely to build a computer using those for you either, but have sold individual phase change units in the past.
It seems a reasonable premise that if you cannot handle the trivial task of plugging components into a motherboard, you won't fare well with below ambient cooling. Weirdly the blog in your sig appears to show you putting together a DIY SAN in a 4U chassis.