You have very few alternatives for a completely fanless power supply. In addition to the one linked above, Seasonic also has a 460W unit, same size as the one above.
Silverstone sells a fanless power supply called their Nightjar.
http://www.newegg.com/Product/Produc...one-_-17256055
Again, not cheap. And I'd think you'd not find a very small power supply that is fanless due to the amount of heatsink that has to be used and exposed.......
An alternative is to look into Seasonic's X-series of power supplies. While not completely fanless, under low loads, the fan is turned off due to the high efficiency of the units. The fan does engage typically at half of rated output, but even then, is very quiet.