- NOTE: This theory is based on next week's episode's trailer **
Next week's trailer, for those who haven't seen it, has a scene with Frank Lapidus asking "What's in the box?" referring to the box that the weird 'what lies in the shadow of the statue' are controlling.
My theory is that John Locke's body is in the box, as he is dead (remember, Dead Is Dead). The John Locke that is walking around with Richard, Sun, Ben and the Others, is the smoke monster. This would explain why hey would want to kill Jacob, why he is all of a sudden so knowledgeable about the island and why he so conveniently disappeared when Ben was judged by the smoke monster.
Think about it, the references, such as the smoke monster incarnation of Alex telling Ben to follow Locke's orders; Ben telling Sun that he can't control what was going to come out of the bushes in 'Dead Is Dead', intending it to be the smoke monster, and (if my theory is true), it was!
Anyway, that was my first Blog, just thought I'd say what came to my mind about it!