I was thinking Anakin becomes Darth Vader at the end of the Clone Wars microseries, especially since there's a teaser of him and who appears to be Mace Windu in a duel. Adding to that is the voiceover that is vaguely Vader-ish but that might be the new General that'll be in Episode III. The only problem with that theory involves Luke & Leia.
Now what any of this has to do with the current thread, um... I don't know. I still think the Rock should've been a Sith apprentice so the next movie could've been Episode III: Know Your Role.