Well this chapter made me fully believe that Danzo is actually Madara/Tobi. When you compare Danzo on that last page to the small part of Madara's face that you see when he starts to take off his mask they look almost identical. Not to mention ANBU's Root division which Danzo leads is said to be similar to The Village of the Mists teachings (i.e. Bloody Village in the Mist or something was it's nickname) fits in very well with Madara also being the Mizukage. Also the fact that Itachi trained under Madara means that Madara must of been somewhat close to Konoha often, which allowed Itachi to track him down. Not to mention the most obvious fact which is that Danzo keeps the eye that Madara uses for his sharingan constantly covered by a bandage, their hair styles are also almost identical, I've also been told that Madara has pins in his right arm (although I can't find the chapter in the manga that supports this) and Danzo's right arm is always in a sling.
Image of Danzo from current Chapter:
http://www.onemanga.com/Naruto/421/17/
Image of Madara without his Mask:
http://www.onemanga.com/Naruto/397/03/
One the topic of the destroyed mountains near Naruto, I think that means that he might be able to through the Rasenshuriken now.