It seems there is a new Paper Mario game in development by Intelligent Systems. Nintendo-fan and credible insider tweeted that "5 sources told us a new Paper Mario will be announced this year for Wii U. Developed by Intelligent Systems."
She further explains the "game is currently being localized and tested". While some say Emily Rogers is as inaccurate as analyst Michael Pachter, others claim she is correct 90% of the time with her behind the scene intel. Time will tell whether Paper Mario will make his way onto Wii U, no offical announcemnet by Nintendo just yet.