This is my KNC Mercury happily hashing away at 143GH, 91C.

Notice the custom book-based thermostats and mandatory thermal "overlay insulator".

The PSU is stuffed in there to get the temperature up, the beaglebone fans are OFF, main unit fan is ON.

Its stable and it works, though. Dunno for how long, realistically.

http://i.imgur.com/L4Oa424.jpg