So I picked up one of these:
Wireless Laser Mouse 6000
It's similar to yours TK, but the design regarding the natural grip isn't as extreme. It was, however, the closed approximation that was available at the store I went to. I'm using it right now. It's certainly more comfortable than a standard mouse. And the wireless is way less annoying, considering I've been switching the old mouse between computers for months now. I don't really need a scroll on the mouse for my PC.
9er, they didn't have a single trackball mouse despite having two sections: one for notebook/portable mice; and one for "standard" mice.