Yea...I doubt the Mizukage (Tobi) will be there.
1) If he did, it'd have to be w/o the mask because too many people know the man in the mask is with Akatsuki. But he wouldnt go w/o the mask in case someone would recognize him.
2) If he went, it'd blow the Tobi=Danzou theory, and I think Kishi likes to keep us guessing about that stuff, so he won't do anything to blow any of the theories, not for a little while more I think. Probably not till Tobi is ready to make his move w/o using pawns like Akatsuki and Sasuke.