A good while back, someone, I think maybe Thermaltake and someone else, made an external heatsink design for Socket370 I believe. It was a metal block on the socket with a heat pipe going to a very small radiator encased in a plastic tunnel a few inches long with a small fan blowing air through it. It didn't work very well. But it was very small.
That silent PSU looks like a very bad idea. Sure, it's got a heatsink on the back, but the contact area between the external heatsink and the internal is very small, and isn't exactly going to be the best interface. The fins inside the PSU are also going to be radiating heat, and there's nowhere for that heat to go except up and into the case. Passive vents above the PSU going to the rear on a tall case wouldn't really help much, and installing a fan defeats the purpose of the silent PSU; a hole above the PSU as the review showed would help somewhat though.
The extra fins arranged all over the inside, on areas where the heatsink isn't touching anything, seems like tacit acknowledgement that not enough of the heat can be transferred to the external sink.
Besides that, for a 350W PSU, those are some absolutely terrible numbers. I'm not sure how they get away with calling it a 350W PSU. There seems to be a version 1.2 with much better output levels though. But 235 bucks for a power supply?! An Antec 330W PSU puts out about the same power levels and is as near to silent as it's possible to get using fans and costs 20% of that.
Good review methods though. Would have been nicer if they'd canned the thing due to not actually being what it claims to be.