My friends please, the kyuubi is strong alright but remember he was taken down by Yondaime-sama (the fourth) using the forbbiden justu, the god of the Death. As far as Uchiha Madara, we know hes capable of achiving the powers of the deamons inside Narut, Gaara and many others like them. Internet sources have reavled that Madara created goodof moon justsu and Kaleydoscoupe Sharingan. Indeed the episodes dont mentioned Madara and the kuuybi ever fighting but he does mention eyes more sinister than his. What does that tell you?! Its a facat now that hes more powerful tha Itachi and Orochimaru, although we dont know why he left Akatsuki we are certian Orochimaru searched for the Sharingan maybe to stand a chance against Madara's power.