I wanted to cover the mainboard of my Anet A8 but i didnt like a big cover.
The cover from Leo_N http://www.thingiverse.com/Leo_N was a good solution but i only got a 60mm fan here from other projects.
The thing from smat06 http://www.thingiverse.com/smat06, http://www.thingiverse.com/thing:1938371 has a pipe from 40 to 50mm and looks great so i took the design and create a new one that fits to my 60mm fans. Also i wanted a switch to put the fan off/on.
To adapt the switch i made a simple add on. The hole for the switch can be break out from the cover.
The pipe got holes for M3 nuts., You have to press the nuts in carefully with a pliers.