For SI: I really want to see a royal guard, and i think it would make sense since they do become members of the dark council.
For anyone: Since watching the clone wars i really want a MagnaGuard droid, mostly because i think they look ****** especially with those capes, and it would make electrostaves less useless. I would also like something like the B1 battle droids, a completely idiotic droid who is mainly comic relief.
http://starwars.wikia.com/wiki/IG-100_MagnaGuard
http://starwars.wikia.com/wiki/B1_battle_droid