Nintendo surprised us today by announcing a brand new game, and it looks like it will be a mix between Paper Mario and the classic Mario and Luigi games for the 3DS.
https://www.youtube.com/watch?v=i7y3FJfNSbg
The game will apparently draw heavily from both series of games, as you can see both the RPG versions of Mario and Luigi as well as paper-crafted versions of the brothers. It is being developed by Intelligent Systems, and you can expect to hear more as we get closer to Spring.
Mario and Luigi Paper Jam will be coming out in Spring of 2016.