The basic idea for the Weramouse V2 is good—a portable mouse for places like the living room that you hold and operate like a gun/Wii Nunchuck—but does it really need a trackball for cursor movement?
Not sure about you, but moving my thumb around in such a short motion, over and over again doesn't seem comfortable. Who knows though, maybe I'm wrong. I do, however, like that the button under your trigger finger serves as the left click.
Technabob also dug up a hidden page which shows they're working on a trackpad version of this mouse, but what about one with a thumbstick? Anyways, you can get the Weramouse V2 for $100 over at [Weramouse via Technabob].