The R2 Gaming Mouse Mark II is a 1600 dpi input device that takes an unusual approach. It's aimed at hard-core gamers, and is highly customizable with seven buttons to which you can assign a function, keystroke or macro. You can even program those incessantly blinking LED lights.
Those seven buttons are far from conventional, too. There are those four immediately-obvious blinking buttons, and then there are three pressure-sensitive zones in the grip section of the mouse. Even the bottom of this device has been reengineered, substituting ball bearings for the usual slippery skid pads.
Check out this video tutorial for the R2 Mouse, plus more pics and a link to a review:
The guys at Hardware Review liked it, however with a few reservations. At $59.99, you might want to wait until the Mark III is released if you're looking for perfection.