
not this again...

The video came from Nintendo's own website: Wii.com. This leak is from Nintendo itself. It has been confirmed by several sources.
Including Wikipedia. The security of confirming characters in wikipedia is tight. The policing there is harsh. But yeah, after much consideration, they did confirm it. They site their source as joystiq, which sites their source as youtube which sites their source as wii.com.jp. Even on that website, there is a glitch that will allow you to see what they covered up. Read about it in the Wikipedia discussions.