A Jinchuuriki with 0 tails? Then he wouldn't be called a Jinchuuriki if you think about it... that'd be pretty funny though =] On the other hand, Tobi = Obito is pretty unlikely even though they have a LOT of similarities like their goofy behavior. Obito got the right side of his body smashed by a boulder or rock right? After that, more rocks fell on him so it's likely that he's dead. Even if he did survive, he'd be missing his right half of his body. His left eye would be missing (most-likely is because of his mask). I believe Tobi = Obito, but hints show that it's unlikely like I said earlier.