i think tobi is already the izanagi form of madara which is why he only has one eye. the real madara died against the 1st which is why he was able 2 be brought back and remember the "plan" he mentioned before.
this guy is the closest one out of any of you to having a brain.
Madaras had a discussion with kabuto through muu when he was revived through the edo tensai. During that convo his connection to tobi was revealed. Plans must not be going accordingly. terms like "he" "him"
the 2nd point is about tobis identity.
the last reference of tobi refereing to himself as madara was his fight with..........paper lady. he fought that fight to look to the future.
during his clash with naruto at bijuu fight city. he said he was nobody and didn't care who he was.
honestly the outcome of his identity may just be impossible to guess. the evidence may not be there. like in a mystery book or something.
3 possibilities we've heard.
it is in fact madara in some split chakra or genjutsu form or something....
it is a character from the past that we've seen
or it is a character we've never seen before.