Sphinx on 23 June 2011
If development begins in early 2012 I could see a holiday 2014 release. It's a little confusing though due to the multiplat element. Will the 3DS and Wii U versions be practically identical? Or, will each feature unique stages, characters, etc. If the latter ends up being the case, the development cycle may be extended.
Overall, it's difficult to say at this point.
