We have six Imperial personas, most of which are flexible enough to be used for other factions with careful use of the mission editor. One of them is really gung ho about crushing the rebellion, so he can only appear in certain missions.
I think we've only got three Alien personas at the moment. We could definitely use one or two more pilots speaking something that sounds like a Star Wars language. If anyone can do something resembling Nien Nunb or Bib Fortuna or the weird eyeball on a stick that pops out of the door at Jabba's palace, that would be awesome!