I actually have played as two Sith lords in a few Star Wars fan-fiction roleplaying websites, and I currently still can play as them whenever I feel like it. Their names are...
Darth Providence
and
Darth Zealous
Also, the rp websites I go to allow us to have our own Sith look's be whatever we want according to whatever avatar we have set up for them. Providence looks like Naraku from the Inuyasha anime and Zealous looks like a grey-colored version of Carnage from the Spiderman comics. Just felt I should add that in to show more into what kind of personality's they have.
I also rp as other characters who are not Sith in those websites, but I'll only mention my Sith one's here.