Retro says Wii U is “a powerhouse”, new game has been in the works for a few months

[Mr Khan]

Soundwave said:
Nintendo will never let a Western studio develop their own IP from scratch again IMO. Next Level Games is probably working on Luigi's Mansion 3 and if EAD is bored of Mario Kart, Retro will probably get Mario Kart 9.

With the amount of oversight their studios tend to get from corporate, it would hardly be "their own" in that sense. An idea with input from the SPD groups that work with the other first-party studios would still have enough central control to be desirable while allowing for original thought.