there's also an "ARCTIC COOLING BREEZE Pro" 92mm, with variable speed and 4 usb ports. It's usb-powered though, so those 4 ports will probably only accept low-power devices, and no block erupter.
It can be found at 12 EUR per unit in public and online stores here.

I'll probably look into this one, cause i'm actually using a way too big fan to cool my 5 block erupters, wasting energy.
(i for sure won't go fanless with block erupters, they really gets way too hot in a few minutes, if no fan is used).