I know people are tired of the "Tobi is" posts but I wanted to throw my hat into the ring... Looking at this latest Manga I really think Tobi is Obito... Look at these facts:
1. He has the exact same M.S. technique as Kakashi's "Kumai". Kakashi can suck things into another reality and so can Tobi and remember, Kakshi's eye is from Obito.
2. When Kakashi used Kumai on Narutos Ras. he was able to hit Tobi while he was dematerialized. They were both at the same place at the same time.
3. They have the EXACT same hair style
4. Tobi can only teleport using the opposite eye of Kakashi's M.S. We do not know if it was crushed by the boulder, we only know his body was crushed. If it crushed his eye then it would of had to crush his skull which would of killed him. No talking afterwards and offering his eye to Kakshi.
5. He commented on how Kakashi "Still" is a certian way.
6. Do let the age thing throw you off. Remember, Tsunade is a lot older than she looks due to a Jitsu she uses, could a person use it to make themselves look older... To make themselves look like another older person...
7. Tobi > Obito...Obi To... Move the last part around to the front and you have Toobi... Kind of like Pig-Latin... Obi-To > Tobi

I think Zetsu found Obito and notified Madara and they decided to fix his body by merging him with White Zetsu...
What do you all think?