This is just me speculating but in the last 2 episodes of IGN's Playstation Podcast (Beyond!), the Beyond crew talked about how they expect to have PS4 by Christmas next year. In some ways, they even sounded confident. It's possible that they were just assuming/expecting a 2013 release but they're journalists/part of the media and I know they stuff behind the scenes (they even acknowledged that knowing stuff that has not been announced was pretty normal for them).
So yeah, not really a confirmation or anything but going by their recent podcast statements/conversations, IGN's Playstation crew expects PS4 to be out by Christmas 2013.