I'm faced w/ the same problem w/ a sff case. I'm giving up and going back to a monster case w/ 120mm fans. SFFs are pretty, but packing them full of stuff then trying to keep them cool AND quiet is quite a stretch. You might could rig up a couple/few 40mm fans there, but the noise will be right in your face, plus you won't get too much performance from it. You're likely better off putting a grille on the 3.5" bay and making sure you've got some decent airflow out the back. <pffrt><excuse me>