I take it back. I think jinxed_wood is 100 percent right and Elena and Katherine will be sharing a body. Check out what Mr. Ausiello just posted:
Question: Any intel on Klaus’ upcoming return visit to The Vampire Diaries? —Kim
Ausiello: It’ll happen in early-ish 2014 and he won’t be making the trip solo. Bonus Scoop: The Katherine-Elena dynamic is about to get a lot more complicated (if that’s even possible).