Got it!
I had to break off the tabs on the fan to get it to fit, its sitting right against the bump where the handle is, its a perfect fit, i didn't need to use any screws to secure it.
It stays in place fine.
The fan i used is a generic el'cheapo 80mm PC case fan, it does not make too much more noise, its a bit louder than the hard drive by itself. When I put it to sleep it also turns the fan off too. It appears that the cube cuts the power to the drives when it sleeps.
