I don't know. Gendy (I think that's how you spell the cartoon creator's name) was inspired by that concept art. Plus, she's not really a Sith. More of a Dark Jedi that Dooku has as a strategist and bodyguard.
Also, there is a new bounty hunter. That makes three total that I have seen (Jango Fett from AOTC, Cydon Brax from Clone Wars video game, and the new guy in the cartoon). His name is Durge, and he is huge and menacing a looks like a robot, but he's not...I think. I read somewhere that he can reattache his limbs if they are severed, so I think he's a cyborg of sorts.