This is a fake gadget. Of course it is; after all, these days it seems like the top trend in gadget rumormonging is to tack a cell phone feature onto some other device and say it's "in the works." There was the iPhone, which turned out to be real, and the Zune Phone, which looks like it will turn out to be real. Now here's a Photoshopped "Wii Phone," as seen on Gizmodo, which is certainly not real. Yes, Gizmodo has reported that Nintendo does have a patent for a gaming phone, but I'm guessing it won't look like this.
Presumably, this hypothetical device would actually be a separate handheld gaming system, not a Wiimote, but it'd be funny if it could be used as one of the newly-iconic controllers. Instead of caller IDs, it could display the Mii of the person who's calling you. But it could lead to some difficult situations: when you're playing Wii Bowling, and the "phone" rings in mid-game, do you pick it up or keep trying to go for that strike?