Mackbrush.com for brushes. Earlmich.com for brushes,and 1-Shot. AND search the Hamb archives: http://www.jalopyjournal.com/forum/search.php
The Eastwood catalog is also a good source at www.eastwood.com. I would use those previous posts you were given too.
here's where I go, get my brushes from the local paint shop, they usually have a couple 00 Macks with dust on em... http://www.tcpglobal.com/airbrushdepot/