Not following whats sasuke got do with the fox recognising or not recognising who tobi is from just looking at his sharingan? Speaking of the sasuke and the fox meeting the fox commented on sasuke's chakra not the sharingan in particular. So he may have done the same with tobi sensed his chakra or something.
To answer the questions about the hair and masks...
I believe we see Tobi wearing different masks because he had been involved in more than 1 serious shinobi battle whereby a mask would have been damaged or lost. The 4th Mizukage comes to mind, where that fits the timeline with the switching of masks I am not sure but it stands that in a serious battle a strong shinobi would need to unmask Tobi depending on which reasons are known for fighting. So, each new mask would be a significant indication of a new Tobi era; post awesome fight or achievement.
His hair changes length not only for any possible reason associated with changing masks but also, and mainly, that this incarnation of Madara simply ages. Perpetuating youth or life in the manners of Orochimaru or Tsunade do not suit his style nor his aims; not to mention he has his own method which suits both. The more plant like "zetsuness" that claims Madara, the more likely he is to keep his long lockes =p If we were to see that Tobi is now 80% or more a zetsu like state then he probably looks like Zetsu with a short head of hair. Heck, I bet Tobi lost his original head in a shinobi battle, probably one where he lost a cool mask too.
@psukkar: even sasuke demonstrated how much control his sharingan had over the fox when team 7 first were reunited, so i would rule it out
If you're implying that because Sasuke suppressed the Foxes chakra, that that means someone other than Madara could also control the Fox, then you may be misconstruing what happened.
Sasuke surpressed the chakra that was leaking out of Naruto's seal when Naruto became emotionally unstable by seeing Sasuke. This is not the same as controlling the fox himself free of the seal.
I am not perfect and I defy you to prove otherwise
Growing Old Gracefully is an Oxymoron ... Mostly Moron !
edit: Whoops, I just realized that Madara was short haired when fighting Yondaime, scratch most of this post. The mystery sickness of Itachi was probably still a factor in ending Madara's life. Maybe he died in a ninja battle or from succumbing to disease but not until after Nagato was born. Nagato is how old? A little older than Yondaime, correct? My understanding of the timeline needs some work to better reconstruct events.
edit2: Oh gosh, I just realized that Madara had long hair when recounting Itachi noticing him for the first time. Itachi totally could have killed Madara. There are some inconsistencies I cannot yet account for. The fluctuating hair is a real wrench in the works because who was who and when were they who?!?!
Last edited by knife eater; 10-19-2011 at 03:40 AM.
The only link we have between Senju and Uchiha are the sons of the Sage of Six Paths. Far as we know, the enmity between the 2 groups hadn't allowed for interaction before Konoha's founding. And after the founding, Madara is the one least likely to have propagated with the Uzumaki or Senju Clans.
What if Madara abducted Nagato during the destruction of the whirlpool country while Nagato was a baby.
He had no memories of being orphaned or his village being destroyed, and lives his younger years through a genjutsu believing he has parents. By using leaf shinobi to murder his "fake" parents, not only did Madara help unlock Nagato's rinnegan, but he planted a seed of hatred for the leaf within Nagato.
****all speculation, if you intend to bash the theory, please don't respond, as i didnt really think about this before posting this, so i don't intend to defend it****