I had to run out for a while at work and I could not just pass CompUSA so being a man of more money than brains I picked up the first one listed with the trackball.
I have not tried it in the vehicle yet but on this machine this thing is awesome and may be just what the doctor ordered.
The trackball feels a little on the cheap side but it could be because it is new and tight but the range is phenominal. I can control it from 10' away, the manual says it is good for up to 66'. There is a mode button on it that turns the left & right mouse buttons into volume up/down, an esc. key, alt-tab key and two macro buttons used to launch explorer & mail. I'm sure those can be made to launch something else, this I will have to tinker with.
It takes two (2) AAA batteries and even has an on/off switch so you can preserve them. No drivers are required, just plug the USB receiver in & go. Just working with it for a couple of minutes it is already comfortable. I can't wait to give it an honest run in the truck.
I'll write again.......