However, if it's statements for dramatic effect from Tobi, you needn't look far for those, either... Tobi does this quite often!
(I wanted to respond, but I don't think I made it in time).
What chakra type are you?
Ok, so here's my question:
If you are an uchiha, who awakened his own MS, then you lose your eyes for whatever reason and you take the eyes of another uchiha (since it's not a close relative you don't awaken EMS). Will you have to go trough another process of awakening the new eyes (like, losing someone dear again), or since you mastered your own MS in the past, you have the ability to awaken the new sharingan MS without any ritual?
Currently, we don't even know if it's possible for someone else, other than the original owner, to awaken MS. We don't know how it was with Obito's eye, but we know, from Shisui's example, that if the eyes were awakened previously before transplantation, you would still have access to MS after it.
It would be wise to mention some facts:
1. MS is rare.
2. Killing your closest person, might awaken them.
3. Uchiha whose chakra/spiritual energies were mentioned to be abundant, strong, have awakened MS.
Based on this, if I were to guess what really happens, it would be that... first, the mind is connected to the soul (I think it was even mentioned, but I'm not sure). The instability of mind, caused from the shock (of killing your closest person), would in turn make your Soul, thus Spiritual Energies, go wild as well. At that time, the uncontrollable Spiritual Powers of Uchiha are poured into the eyes, if the Energies are strong enough, the eyes evolve to MS.
If that were to be true, the real condition would be: great Spiritual Energies, strong enough to evolve the Sharingan and the moment/event that would make them (Energies) go out of control, and of course the Sharingan itself .
This would allow even a non-Uchiha to evolve Sharingan into MS, if he/she/it had completed the condition above.
Q: Why didn'y Minato and Kakashi make sure to find Obito's corpse, after the mission at the Kannabi bridge was over? WOuldn't it make sense for them to recover it to give him a proper burial? If I were Obito's friend, I wouldn't accept for his corpse to lay abandoned in the middle of a forest. Maybe they did search for him but he was already gone? In that case why didn't they investigate the case further? The times of war didn't permit them to engage in supplementary research or did they simply think they couldn't find the right plave anymore? Something stinks to me here...Obito was given a grave, but if he's here, it means it was empty and just symbolic. OR was Obito's dead corpse exhumated by whoever uses it?
Obito wasn't given a grave. He was given a monument, or rather his name was inscribed on a monument, which carried names from before his time as well as those after, like Hayato's, who was killed right before Oro x Sound x Sand sneak attack, while spying on Baki-Sand Guy (he basically sacrificed his life for the village).
On the other hand, it was Rin that was given a grave, which means she died at time of peace with her body retrieved, without risking her life for the village. Frankly speaking, you better be prepared for some rape scenes or implications... after all, she was one of the most beautiful characters, not to mention Kakashi's Thousand Years of Pain combined with Raikiri, seems like an ideal way to, take revenge for you know what... nah this is shounen, they can't even suggest that... I think .