Yeah, that's my thought. I also want to expand/alter my thoughts on the new Ep III:

The opening crawl would establish that there is a ring of special assassins working for Palpatine and swearing loyalty. Anakin would be established as among this ring, and this would be his motivation to kill Mace and defend Palp. We would never hear him referred to as Sith in the movie. He would still kill Dooku, depriving Palp of his apprentice, but we'd never know who took his place. We'd also hear rumors (established in the crawl) of a deadly assassin called Vader, and Palpatine would even give hints about him to Anakin, but no one would know who he really was or if he existed. Anakin's loyalties between the Jedi and assassin's ring would be strained, and finally Anakin would choose Palpy, from whom he believes he can learn the secret to immortality. He knows that Palpatine is seeking a new apprentice from among the ranks of the assassins. He fights Obi-Wan as an assassin in league with the Sith, not as Lord Vader. He of course loses and we believe he is dead and we never see Anakin recovered by Palpatine. In the end, we see an unknown individual in armor identified as Lord Vader, apparently Palpatine's new apprentice, but hopefully we come to believe they are separate individuals.

Just running thoughts late at night, so hopefully it makes sense.