Art threads:
Slimin112
Barsukov
Brandish
DStraX
Nezumi Works
Lord Venom
Raybon
Netridelium
Spark_Zero
cz64

Sites I found from CA.org
K'dar's art and miniatures-I found this guy via ConceptArt.org, and he has some impressive stuff. However, this site is in Italian unfortunately.
Android Arts-By Arne Niklas Jansson

I might have to compile all the CA.org thread links and put them in one single thread sometime.