Kensington Expert Mouse. While browsing, the 2.25" scroll wheel controls the vertical and the trackball is left to right. However, in WL or Cubase the two controls reverse parameters. I should mention that when first I tried it I didn’t like it, the horizontal movement seemed too uncontrollable with GUI mixers and even moving around plugin interfaces. Then I saw Dave Pensado using one in a video. What he did was put two fingers on opposite sides of the wheel (like picking up a baseball) and I saw that he could control the curser perfectly, keeping it steady on the horizontal and avoiding the trackball completely (which I was always nudging when turning the scroll wheel with one finger). Doh! So I plugged it back in (always using the Microsoft driver, btw) and now it’s a breeze to use.
As to controlling Cubase, you need to search the Cubase forum and see what is going on with the PreSonus Faderport V2 and two independant script writers, originally a man named WEM and then a different man named Christian (who got involved after WEM took a long break). You don’t have to believe me, but Christian has taken the Faderport V2 to a different Universe! There is no mouse or other controller that can touch what Christian has created here.