I was often up in Redmond around that time participating in focus groups for Xbox 360 and the original Xbox. (You signed an NDA and they showed you all kinds of things about an upcoming game for an hour or two, you gave your opinions, and then they paid you in your choice of games from a selection of titles.)
I swung by Nintendo once while I was up there (it likely would have been this same year, 2006) to see what would be accessible to the public, but it was only a small reception area with a very small set of public display cases. I would have loved to see this first hand, it looks amazing!