That'd be a neat trick. How do they manage this feat? If you have a sensor that's 4:3 you can't change the shape of the sensor to 16:9. It's physically impossible.
Are they perhaps including more pixels and just not telling us about them?
Here's how it's done, FYI (courtesy of Björn of dpreview)
That is to say, unlike other cameras, where the wideangle maxes out only for a certain aspect ratio, Panasonic's TZ2/3 designs will give the same max wideangle and the same number of captured pixels for any of the 16:9, 3:2, or 4:3 aspect ratios. Pretty slick, actually.