Check out this trackball from the China based computer peripheral maker Evergreen. Don’t be surprised by it’s microscopic size, it has all the required features of a regular trackball like click, scroll and the cursor mode. Considering the size, we are not sure how comfortable would you find this trackball to be, but if you like to carry an extra pointing device along with your laptop, this may not be a very bad choice.
The only downside is the device’s support for Windows XP and Vista only. So if you are a Linux fan, this is not your option.