Bluetooth version of ergonomic mouse?

I currently use the Microsoft Natural Wireless Laser Mouse and Keyboard combo. Well I never use the keyboard but love the mouse. It connects via the USB stick. I thought I'd sell the whole unit and get the standalone mouse, which I think is the Natural 6000. The problem is that it has a usb receiver with a cable which i don't want.

So is there a bluetooth version of this mouse that someone has found, or some other mouse that has the same ergonomic features that only has a usb stick as a receiver?

I'm on a Macbook Pro with Leopard.

thanks much!

Magic Mouse is really sweet. I'd highly recommend it. Loving mine. Very easy on the hands.

it's sleek, but I'd prefer something designed with ergonomics in mind. that's why i like that Microsoft mouse so much. the weigh is on the side of my hand, not my wrist.