What I've heard, which again is still rumor at this point but has a decent chance of being true, is that they all play jedi knights, and that they are only cameos - they're on-screen for only a few seconds. The sole upside is that I've heard they are in some sort of battle scene or something and they all die at the end of their cameo, so while they may have made it into the Star Wars mythos, they don't last long, and we can all cheer when they die.
Small solace, I know, but such is life. George Lucas, wherever you are, you're a damn whore.
(Update: this is JUST a rumor at this point, but I HAVE heard it from several sources. To give credit where it's due, the last place I heard it from was on satori1970's journal, here. I'm hoping as much as you all are that it's just a false rumor, maybe some big joke or hoax, but we'll see. Oh, and George Lucas is STILL a dirty old whore even if it is a hoax.)