"Ben was killed off because Guinness refused to do any sequels after Ep 4. All of the scenes that show Ben as a ghost in the later 2 movies were shot ahead of time (probably right after SW was released), which is why some of the shots are a little miscued"

Nooo....actually, that's kinda not what happened, in a not even close kinda way. Original script, and the one Guiness signed to-Ben lives. Halfway through shooting, Lucas changes the ending as far as Ben is concerned, and Guiness, who had been pretty much all that held the U.K. crew together, is so pissed he almost walks. The nonsense over his hatred of the franchise and the fans comes up MUCH later, after the thing blows up to global proportions and he can't walk down the street without being accosted by some fan boy. Guiness films bluescreen scenes for Empire when Empire shoots, not "ahead of time". In fact, has to come back and do ADR at the end of production on some of his stuff because he was sufferring from a horrendous cold when the footage was shot, and the diologue is unuseable.. He returns for Jedi, this time INSISTING that ILM find a way for him do do his scene with Mark Hammil on the Dagobah set, and NOT against a bluescreen (which, incidentally, is why you will notice he NEVER crosses in front of Luke during the scene, AND why the camera is locked during the scene (so ILM can go in and roto the glow in, and composite the transparency). Just thought I'd clear that up.