you know what you could do, find a review on what the highest temp you can keep your psu at is before it starts to do some damage, then stick a temp sensor in any psu you buy... then get a fan in there that has a speed control (or you can use a rheobus)
Some of the PSUs that I work with... you can't hear them at all, and I've heard tons of them. So really, you have your options open, many brands have the fans running so slow that you can't hear it unless you are right up next to it with your ear.
Just out of curiosity though, why do you (or anyone else for that matter) care so much about having something the ABSOULTE quietest it can be? I mean I can see wanting something to be quiet because when you sit at a computer for a long period of time you don't want to be bothered with a loud humming the whole time. But to do research on making sure that EVERYTHING upon EVERYTHING is the absolute most possible quiet just seems a bit too far to me.
I guess it's all a matter of opinion though.