I haven't tried it myself but there is the RollerMouse which you could (conceivably) use with any keyboard.
I personally use a RollerMouse (
http://www.enablingtechnology.net/contour-rollermouse-pro-2-649-p.asp). At first, I was unsure how it worked from the images on screen. I trialed a unit and have not stopped using it since! I can assure you I'm not sales pitching, but, I absolutely love it!
When I go back to using a standard mouse and keyboard, although in reality its only an extra second or so, it just seems to take a long time to pause typing with both hands, move my right hand to the mouse and then back again. With the roller mouse, I can quickly move down to the bottom of the keyboard (according to the manual you are not supposed to reach down and use your thumbs), navigate with both hands and then move quickly back up.
This might only be aesthetics, but, it feels more naturally than swinging my arm out to the mouse. I also like the single buttons for copy and paste. On my Roller model, I have an inbuilt mouse scroll button and a large silver left and right click button. There is a third button in the middle, a double click button, which I just cannot get my brain to adjust to and use.
I could use this button to double click by clicking once but I find it more logically and naturally to simply press the roller bar down twice and hear two clicking noises. Thinking of a single click button for a double click just doesn't come naturally to me.
I've only ever used a standard mouse before and never a roller ball (the one normally on the side which you move with your thumb) so cannot compare it to much else. All in all though, I highly recommend it!
