Orochimaru is acting really sly right now ... I think that he might be planning to take over Madara's body. Think about it ... The Evil Trio (Madara, Obito, and the Juubi) are about to get raped. This will be the final plot twist and will set up Orochimaru as the final villain.
Can you imagine him inside Madara's body, using the Sharingan, Rinnegan, and Wood Element along with his OWN jutsu.
Also, how I think that Orochimaru will take over Madara's body ...
Here, Orochimaru states that Sasuke is different from when he and Tobi was using him. That means that he's through using Sasuke.
And yeah, yeah. I know that in a couple pages, he says he's interested in Sasuke, but he says that he's interested in Sasuke's young body.
But lets think about young. A virtous, powerful body ... Madara practically has a young (died in youthful age) powerful (he's freaking Madara!) body.
Also, why would he and Kabuto experiment on Madara??? Those that say screw over Tobi, remember Orochimaru has no interest in this war which means he doesnt give a shit about Tobi.
How's he going to get inside the body of Madara? The Curse Mark!
Inn one panel, we are shown Anko's neck! It has a curse mark on it. On the very next panel, we are shown Madara clutching the exact same spot!!! Coincidence? HELL NO! Don't even try to make that argument! And for those who say that "Kimimaro's curse mark was on his stomach though" are idiots. Madara has the Heavenly Curse mark, the same one Anko and Sasuke had which were in the same exact spot!
*New: Also, Orochimaru wants to know all Ninjutsu and how it came about and what not. With Madara's body, he could become the host of the Juubi ... giving him NEARLY UNLIMITED AMOUNTS OF CHAKRA AND POSSIBLE FREAKING REVALATIONS!!!
p/s: I know this has been brought up a bunch of times, but just wanted to reiterate