In a portion of IGN's Nintendo Minute Volume 37, Perrin Kaplan said this:
To answer one of your other comments, we still have a lot of our more traditional marketing efforts planned. People will see it all shortly, from ads to many of the usual tactics we use to support our key products. Plus: a few more surprises like the Metroid Prime 3 Preview. And no, I'm still not going to spoil the fun and tell you about it ahead of time!
The way she worded the surprises part made it seem like it was a surprise about anything on Wii, but the article is about Metroid Prime 3, so it could be referring to that. A demo maybe? Who knows. All I know is that Nintendo will continue to be mysterious and that's something that I don't think will ever change.