MGE has developed a new 600W power supply that is designed to operate outside of the computer case:
The unit, called the XG 600, is fan-less and is designed for those who want to eliminate components from their computers. Gabriel Torres from Hardware Secrets has a positive review of the unit claiming the power rating is actually lower than what the device is really capable of. MGE claims that its XG 600 produces a true 600 watts of clean power and because it completely removed from the PC and won't contribute electrical noises and heat to the inside of a computer.
The power supply has an LCD display that shows load and internal temperatures. You can check it out over at DailyTech.