I got a 29 marauder and 27 assassin on The Swiftsure in SW:Tor. I also got a level 2 Jedi kight on some other high pop server, but I can't remember which.
I started my mara first, then decided I wanted to tank, so I rolled an assassin. Darkness tanking is so much fun. When I do heroic (4) quests, I just pull and tank whole groups and h=I've only had 1 healer tell me I needed to CC so far. He was IA healer, so I think that had something to do with it.