There are some pretty need fan/cooling solutions for sale from the server world. they fit intoo 2 inch high rackmount servers. But most of them are pretty loud..

I also know of a heatpipe solution with a low noise 120mm fan that would fit intoo the Groove.

But as long as you don't overclock your CPU heat should not be to much of a problem as long as the airflow through the case is high enough.