Paul Gale Network from Texas has talked to employees at Retro Studios (Metroid Prime) that claim that the developer was one of the first to receive development kits for the Wii 2 (or whatever it will be called). Exactly what kind of game Retro Studios are working on is of course not known, but PGN managed to snag a good hint - they are supposedly working on a "a project everyone wants us to do". Which, we're guessing, is Metroid Prime 4.
If that's true, and the Wii 2 is as powerful as rumour has it, this might be something to keep your eyes on come E3.