Well, I think you've already mentioned all the good ones :P
Platinum could be good, or Mistwalker, and Sega and/or Square could use the Nintendo touch ^^ Besides, they both have certain mature franchises Nintendo could benefit from.
But, what they really should do is buy more Western studios...
I'm on Twitter @DanneSandin!
Furthermore, I think VGChartz should add a "Like"-button.