Apple's strict position on one-button mice could be set to change, as it has published a patent application – originally filed in September 2002 – for a mouse that has an optically based scrolling feature. This turned up last year as well as plans for a mouse with a rotary dial.
Instead of a traditional scroll wheel, the optical touch-pad appears to be based on the iPod's scroll-wheel or iPod's mini's click-wheel, which would make the touch-pad surface tap sensitive. The peripheral device includes "one or more buttons configured to provide a clicking action for performing actions on the display screen".
News source: Macworld | UK