According to some reliable sources, Nintendo is making a new 3D Mario game that should appear in 2013.
Paul Gale Network: http://paulgalenetwork.com/home/2012/08 ... io-bros-u/
My Nintendo News: http://mynintendonews.com/2012/08/20/ni ... for-wii-u/
And although this is not a big surprise, it's good news. After I played NSMB2, I knew I just like the 3D Mario's much more. They are just rumors, but also very reliable sources. And, SMG2's release was like 6 months after NSMBW. Will they do the same with this and NSMBU? For now, we will just have to wait, since nothing (else) has been confirmed. Sorry if it was already mentioned.