I reallly like this theory, I made a thread a long time ago about the possibility of Sasuke being a jinchuuriki, I feel as if Madara planted a little seed in sasuke (no homo) and is waiting for harvest time.
The facts about the massacre told by Itachi and Madara are a bit foggy for me but I want to look at all the possible holes in this theory and see how kishi could clear it up.
Minato seals half the chakra in the death god so it won't be reborn again in the world. Loophole in the narutoverse is probably that a person with a lot of hate can fester and ressurect the yang portion of kyuubi, which is most likely through an uchiha due to their tainted heritage and relation to kuubi itself. You know how Kishi loves to throw an angle, lead you on and end it with an M. Night twist. I always felt that the moon eye plan was flawed. If the 9 bijuus make up juubi then can 8 1/2 of its chakra ressurect it? Kyuubi shrunk in size but can juubi even live without being whole? So maybe Madara expected this and Sasuke is key.
How does Madara know half the kyuubi is sealed and that it can be ressurected through malice? By spying on Minato's sealing and about reviving kyuubi's other half through Uchiha secret writings and rinnegan readings? (Maybe not rinnegan, nagato would warn naruto about sasuke)
All Sasuke fights were manipulated to raise kyuubi as opposed to or rather along with strengthening his sharingan. Madara could've capture Naruto, for instance, before Kakashi and Yamato restrained the both of them, he probably didn't because he needed Hachibi extracted first, but why instigate a fight between his trophy and the one who converted Pain? Madara wouldn't risk his plan for entertainment or curiosity.
Madara stated he wants Sasuke hooked up to gedo mazo right? At first I assumed he wanted to replace Nagato with Sasuke but we know now he gave Sasuke ems not rinnegan. So he probably meant to extract from Sasuke..
Also explains why he easily agreed to give Sasuke to Kabuto when this is done, he has no need for an useless pawn.
Madara also offers Sasuke a bijuu. So far everything he's offered Sasuke, he eventually gives in and accepts. Karin's reaction to Sasuke and Naruto's chakra..come on we know he's evil, why troll it Kishi..oh because its not his chakra?
Why doesn't Madara make himself the container instead? Easy he wants the juubi not kyuubi, and you die when extracted, Sasuke's his sacrificial pawn. He probably doesn't care who wins the Naruto and Sasuke fight, he wants a whole kyuubi.
In conclusion, if this is correct kudos to you and the few others who've thought of this, although I disagree to an extent, I believe this knowledge is exclusive to Madara and Zetsu, maybe Itachi has wind of this, why he put safety measures in Sasuke's eye and why he told Naruto that Sasuke isn't "colored yet".