I don't particularly see the need...Nintendo doesn't release as many games per year than, say, Electronic Arts (even though Nintendo gets more profit than any other game company), and they already have 6 studios to make whatever games they are designing. Isn't Retro Studios, Intelligent Systems, HAL Labs, EAD, Silicon Knights, and NST enough? Not to mention third party partners like Sega and Namco as well as several companies pretty much devoted to Nintendo such as Factor 5, Sonic Team, Camelot, NDCube, and Zoonami.
And EAD alone is the largest development house in the world with about 1000 employees and some very expensive and advanced equipment...not to mention veteren geniuses like Miyamoto...
So it's not as if there is a lack of people to make games.
Of course, there are plenty of other possiblities to consider. Could this be sort of Japan's NST, where Nintendo could gather upstart designers and show them the way...or possibly they are splitting EAD and moving some of its people here?...None of the other first parties are big enough to split. HAL and Silicon Knights both emply 70 to 80 people, but I'm not sure about IntSys, NST, or Retro...