I think that theres too many thing pointing to tobi being obito especially in the way he looks. The whole only see the right eye thing and the hair and the fact that obito was left in the rain country. But then i wonder what was the point to the Kakashi gaiden i mean no other character had a back story so it doesnt make sense unless its a clue. So i started thinking that maybe madara does what orochimaru does in that he takes bodies and transfers his soul or whatever to them. So that if obito is tobi its obito's body with madaras conciousness. And this would also maybe explain how itachi ended up in the akatsuki and why tobi comments on the power of sasuke's eyes compared to itachis as in sasuke might be a better host. This kinda made sense to me because orochimaru didnt get the change body technique untill after he left the akatsuki. The biggest flaw i see here is that madara didnt found the akatsuki well maybe but pain is the leader although he's ordered around by tobi so i dunno but yea. The main theory is that if it is obitos body its madara's conciousness.