My solution to the CC arm problem came from the new Daemon Prince box. That thing comes with 3 extra weapon arms, which can look really good with a little conversion work.
My personal flavor was to use both of the Sword arms, by cutting one sword off at the hilt and glueing it onto the bottom of the other, to create a double-bladed weapon (think Darth Maul). Looks fairly good and i've gotten several compliments.
You'll have to use a bit of Greenstuff on the shoulder to make it look good, because it obviously wasn't made to connect to a Defiler.