Even though I've never entered this awesome tradition, I have been working kinda sorta on some imperial customs for a while, so I could actually probably enter this time!
Aliens is a good idea, but difficult to achieve. Where do you get the fodder to make original aliens?
And don't buy any of that EU crap about the Emperor hating aliens. Clearly he has no trouble with guys like Mas Amedda, a very loyal follower who was obviously in on a great deal of his schemes. EU sucks!