http://gamrconnect.vgchartz.com/thread.php?id=148135
That suggests MS is coming 2013 and if MS is coming...
http://gamepolitics.com/2012/06/06/sony-we-want-be-best-not-first-ps4
Repeats that at E3 2011 Sony said they won't let MS launch before them again, but they don't have to be first overall.. i.e. not an issue Wii U is first.
Its all coming fall 2013.