I would suggest coming up with new storylines for the Hutt faction. Yes, you'd have more than one stoyline for each class, but there can be overlap, especially in the early missions. ed- The game's architecture makes it really easy to add new missions/stories. Hardest part would be doing the new animation/voice acting.

So, how about making the Hutts a full faction? Classes could be Smuggler, BH, Assassin (like Imp agent) and rogue Jedi/Sith.