Immersion liquid cooling is something I have done in the past, and that is all well and good, it is after all HOBBY level tech.
For commercial level tech it isn't even a joke, imagine opening the bonnet / hood of your new 2010 car and finding a big tub full of water with the engine immersed in it.
Internal combustion engines have had closed circuit internal liquid cooling circuits for decades, and frankly computers and electronics have had closed circuit internal liquid cooling circuits for decades too.
Think backplane technology and hollow main boards, the liquid coolant flows through the hollow PCB, and mates and either side with the "backplane".
All the advantages of liquid cooling, and almost none of the disadvantages of liquid cooling.
Air cooling has one great advantage, "leaks" don't matter. Provided you have sufficient mass flow you can leak air all over the place.
Older internal combustion engines didn't even have forced circulation in the closed loop liquid coolant systems, they used thermal syphon, much like the space between the racks.
The salient fact here is you have to design in the cooling circuit at the engine block / PCB mechanical design stage, until and unless you do that you are going to be dealing with some god-awful heath-robinson kludge, like fitting an old "stationary engine" (google it) into a 2010 Dodge rolling chassis.
Instead of a 50 buck case containing a 100 buck mobo, you end up with a 100 buck case and a 200 buck mobo for closed circuit air cooling, or a 200 buck case and a 400 buck mobo for closed circuit liquid cooling, and these prices are for large volume manufacture with full economies of scale.
Now go back to your Dodge dealership and take in two 2010 rolling chassis for the annual service, one is running a bog standard cummins, the other is a kludged up stationary engine, and ask the mechanics which one will be more expensive to service.
Closed circuit liquid cooled electronics are not new, it is routinely used in avionics, which of course means that you can back 200 watts of thermal rejection (a modern desktop computer) into a package the size of an iphone, and run it flat out 24/7.
But it costs.
Unless you are in Hong Kong then the cost of land per acre is cheaper, and air is free, and leaks don't matter, and the coolant doesn't cause shorts.
The only other advantage of liquid coolant is it is much quieter, but even so, you can cure that problem by making everything bigger to accommodate much larger passive heatsinks.
http://hackedgadgets.com/wp-content/_hs2.JPG for example, this stuff is extruded and bought by the metre, it doesn't have a failure mode.