If you are willing to spend some dough...
Get a mnpctech.com modified Tsunami:
http://www.mnpctech.com/TsunamiVA3000.html
...however, you can request the mod be done to a case with a window...
mnpctech will probably raise an eyebrow and make the same point Galvanized did, but they probably would accomodate your wishes. Putting in some quiet gear would help too, though I am no fan of "fanless" heatsinks, as most will not be up to the task. Personally, I think a Zalman CNPS9500 (or the yet-to-be-released CNPS9700) would be preferable and look nice (blue LED fan) in a case with a side window.
Stock cooling on a 6600GT? You probably can get alot quieter; get something like the Zalman VF700 (with LED, since you want a side window).
Just some ideas... take what you will.