I've ordered a aerocool dead silence as im doing the exact same thing as you (downsizing from a 600t)
Not many people have spoke about them but they've got pretty decent reviews. Ill post up some pics when i get my build done but im awaiting a fatality professional m board and a h100i cooler.
Have you looked at the BitFenix Phenom MATX
http://www.overclockers.co.uk/showproduct.php?prodid=CA-147-BX&groupid=2362&catid=1850