seems to me that Tobi was able to negate, and when Kakashi says "don't tell me..." it's because he realizes that Tobi has a similar sharingan to his, namely Obito's. I know that Obito's body was crushed, but we have seen Tobi using Zetsu to create new body parts, and when we see Tobi fight the 4th, his left side of his body (the same part that Obito had crushed) is the part that begins oozing like a white Zetsu. I'm not saying that Tobi is Obito, I still believe that Tobi is either Izuna or a part of Madara that was carrying his will, and needed a sharingan to become whole again, hence where Obito's crushed body comes in. Up until then, Konoha had done a pretty good job keeping all of their deceased doujustu users within the confines of Konoha (as is apparent by the mass build up of sharingans on danzo's arm). If they never recovered the rest of Obito's body, it wouldn't surprise me if Orochimaru was able to scoop him up and recreate Obito to be a vessel for whoever the real Tobi is. Plus, if you change the kanji around in Obito (Obi + To) you get Tobi (to + obi). This would also explain why Tobi knew characteristics of Kakashi and Gai, for he would have the memories that Obito had before he died.
Tobi and Kakashi's time/space jutsu and Kamui look pretty similar... don't they? It would make sense that Tobi could counter Kakashi's Kamui with Obito's other sharingan. I think that's what Kakashi realizes when he says "don't tell me..." it is also possible that the appearance of Tobi/Obito would change due to whatever experiments Orochimaru was performing. Oro was a member of Akatsuki, and he left just before Tobi came back in (even though he claims he was the reason Akatsuki formed in the first place.) This is probably due to the fact that Tobi used some sort of body switching technique, similar to the one Oro uses. I think in the next few chapters, we will be seeing how much Tobi and Orochimaru are connected. Tobi does attack Kabuto at first, so he too must hold some sort of grudge other than Oro abandoning Akatsuki, could be the Obito in him ticked that he's being manipulated. Obito was never resurrected in the war too, i was thinking that would have been a good emotional tool against Kakashi... for that matter, other than Madara and Itachi, there weren't really many sharingan users resurrected in this war... given how well the 2 that were resurrected did (sure Itachi kinda backfired...) don't you think more Uchiha would have been used? And furthermore, when you resurrect an Uchiha, would you get them before they had their eyes scooped out?
