I believe it when it the World's Largest Plasma TV is really in Shops this Christmas, but Panasonic just announced this in a press-release.

Panasonic showed the 103" 1080p HDTV at the CES 2006.
The 103 inch Panasonic Plasma HDTV features a 3000:1 contrast ratio. I currently have my LCD projector throw a 103" image on my wall. It is hard to imagine to actually hanging there a Plasma TV with the same size.
Panasonic omitted the most important aspect of this amazing piece of equipment - the price.
Panasonic is actually showcasing the world’s largest plasma television at the New York Stock Exchange today, just in case you hang out there.
More details in this Panasonic press-release. Via NewLaunches. More photos of the 103" Panasonic Plasma HDTV are available on Yahoo!.

Check prices on currently available Panasonic Plasma TVs.