Iwata briefly mentioned a crossover game that brings together Capcom, Sega, and Namco Bandai for a new 3DS project. Details were not announced other than the game will be released under the Banpresto label. Banpresto handles crossover titles like Heroes Phantasia and Super Robot Taisen games.
Pretty much this maybe either 1 of 3 things
1. The obvious a fighting game weither standard 2D or Smash Bros style
2. Crossover ARPG with Tales of Battle System or is like Monster Hunter
3. Super Namco-Bandai x Sega x Capcom Taisen (I doubt this one will happen though)