Apparently it wouldn't work unless it was water cooled. It wouldn't be able to be kept cool using a normal PC fan-system.
??
Not entirely correct.
CPU and GPU have their own fans and will therefore be sufficiently cooled with a room temperature air-stream and not with the heated breathe of a PC-case.
Since the temperature of the environment will normally not raise above room temperature (max. 21° C) a fan cooling for RAM and HDD is not required. In addition the massive back plate should work as enormous heat-spreader, provided of course that the components are mounted correctly.