3-inch HD Camcorder: How Small is Too Small?

I'm all for portability, but when you're toting around an HD camcorder I'd like it to be big enough so that I'm not constantly worried about it slipping out of a hole in my pocket. No dice if the camcorder is this "MicroHDTV" from the Fraunhofer Institute in Germany. It's a mere 1.5 by 3 inches, which is just plain silly.

Despite the size it an purportedly pump out 1920x1080 resolution, which isn't too shabby. HD helmet cams, here we come.

3-inch HDTV camcorder from Germany [Crave]