Tobi (without rinnegan) VS Itachi This is a fight between the two using their own powers (that we've seen so far) so :
No rinnegan for Tobi
(assuming its not his, remember this means no rinnegan powers either -.- )
No tailed beasts
tools can be used so Yata mirror , sword of Totsuka i.e and just normal swords you get the point
other then this the rest has no restrictions any other technique of theirs can be used so tobi s/t , genjutsu i.e ..
who wins? they both are very intelligent and have strong range of jutsu's but i think just because tobi is having an identity crisis itachi can use izanami on tobi , because it was designed for the uchiha to accept their fate so also izangi wouldnt work would it, idk you tell me ? but then again tobi has alot of chakra and could last longer then itachi or break out of any genjutsu of itachi's ...
i'm not really sure so who wins ? :D