How about heat-pipe cooled Power Supplies? No, not little ones like 400w, but a beefy 850w Zalman 850-HP!
Going for SGD$ 399 at ProLink Data, it is probably going to run very silent, the fan may not spin much with such extravagent heat-pipe cooling employed.
Also at ProLink Data, SGD$ 100 lesser at $ 299, the new Silverstone DA650:
This 650w unit is a modular unit under the Decathlon series. It spots a single powerful +12v rail of 54A.