Intelligent Systems - are probably also helping out with Fire Emblem X Shin Megami Tensei as well.
Alpha Dream - I wonder what Alpha Dream are working on? I doubt we need a new Mario RPG right now but they could be working on a Wii U project maybe?
Camelot - Now Mario Golf is all out i wonder if these guys could be working on a new Golden Sun? It seems within rotation...Mario Tennis...Golf....Golden Sun....Tennis....golf...Golden Sun....
NST - Mario VS Donkey Kong...it seems like these guys are pretty small for an internal Nintendo studio, so i doubt they are working on anything else other than this at the moment. Would be nice to think that they could be working on a new WaveRace or 1080 though....
Grezzo - I am convinced these guys would be working on Majoras Mask for the 3DS (should such a thing exist...)
HAL - These guys are seemingly allowed to whore Kirby as much as Mario. I don't get why though, its not like I don't like Kirby games but there are so many Kirby games and i wonder how well they sell compared to other franchises. I guess HAL are probably also helping out with Smash Bros as well?
Next Level Games - These guys are working on something interesting, they announced that they are working exclusively with Nintendo but then didn't actually announce what they are working on. I thought Luigi's Mansion 2 was a good game so I would be intrigued to see what they come up with next.
Level 5 - They had a trailer for a game called Fantasy Life at E3 which looked interesting. They announced either last year or this year that they are working on a new Professor Layton game as well.
Ive been playing Attack of the Friday Monsters and Liberation Maiden and thought they were good games so i reckon any other eShop games from them would be good too!
RARE.....well we could always hope for a new Perfect Dark, Banjo Kazooie, Jet Force Gemini, Blast Corps and Conkers...but they'll probably put out another Viva Pinata...not worth buying an XB1 for that!