If one were to take a look at the accessibility image of the new iPad on the apple website, one would see the one and off switch on the white on black settings screen. As one would notice, the on and off switch is in a square shape. As everyone knows, only iOS 4 and below have a square switch while iOS 5 and above have cirular switches . To prove that this is not iOS 4 or below one can see the notifications tab on the left hand side which comes only in iOS 5.
There are only 2 explanations to this
1. Apple is testing iOS 6 on the new iPad and by mistake put up a picture on their website
2. Apple downgraded the new iPad to iOS 4 which is extremely unlikely
Some people may argue that the picture on the apple website has the iPod tab instead of music and does not have I cloud, messages, or twitter, but apple could have moved these icons down and returned to the iPod icon
WWDC 2012 is only 2 months away and with the sneak peek of Mac os x mountain lion, this could very well be iOS 6.