Here is my sith, lord Siferus. Now, i know there are only ever two sith, but here's my idear. There are hundreds of sith, they just don't know it. The sith part lies sleeping in them, but when a sith is killed, another wakes up.
The great lord Siferus and his speeder.
Lord Siferus kindly showing us some tricks on a poor rebel.
It's always good to see a new Sith in town ... and i'm the same way about that 'rule of two' ... sure, it may have served it's purpose in hiding the existence if the Sith for along time ... but sometimes you gotta break the 'rules' (as i have done also). To see how i bent the 'rule of two', check out my Star Wars ~ Lego site !
Always check official continuity. If you want information on the Sith try googling Sith+Wookipedia. That should pop up a massive amount of backstory on all things Sith, dark Jedi, ect. I think most Sith are to plain and black (this by no means states I want you to add some red) and they become a rather reduntant stream after one looks at to many. The swoop is interesting though. Personally, I think it should be a bit more rounded.
the speeder looks very fragile and what are you talking about sith's ?
there was (according to the starwarssage) a clan of siths.
The speeder looks good, but you should work some more on it and a jedi or sith has almost always a starfighter under his control