A LinkedIn listing for an employee at Midway Games has suggested that work on an undisclosed title for Xbox, PS3 and Wii2.
It could be an accidental, even an intentional typo, or perhaps an indication that some studios have gotten their mitts on assets for the Wii's successor. Whatever the case Nintendo and Midway will likely refuse to comment, so it'll be sometime before we find out more information.
Thanks to GoNintendo.