Even if that fight happens there is no way that Orochimaru will ever obtain Sasuke's body in a million years because that will just destroy the whole story, so he's bound to loose. Also I don't think that Karin, Suigetsu and Jugo will just sit back and enjoy the show.
Kabuto still has DSM and the abilities of the sound four, Orochimaru's body is too shitty to obtain Sage Mode. That's why he can't use Sage Mode, that's why he wants Sasuke's body. DUH!
Yes it's true, Orochimaru took back his own Chakra from within Kabuto but I think it's obvious that it wouldn't/didn't affect Kabuto in a big way. At most from this setback, Kabuto would be unable to produce the live manifestation of Orochimaru and that's it!
You must be registered for see images
In regards to Kabuto's own power, I've said this to so many people. You can't just wake up one morning, click your fingers and BOOM you're a sage. You have to have the ability, patience, practice and knowledge to become a Sage and achieve Sage Mode which is something that Kabuto mastered by himself at Ryuchi cave.
You must be registered for see images
It would be a tough cookie, neither character would get stopped straight away that's for sure.