According to a recently published patent filing, Apple is working on a cheaper version of Multi Touch. Although Apple tried to use plastic in the original Multi Touch, certain drawbacks forced them to use the more expensive glass instead. But, with a newer material—polyethylene terephthalate—plastic becomes a viable and inexpensive option for use in Multi Touch.
According to the filing, plastic Multi Touch would able enable the display and touch surface to be free of other circuitry, making for a more durable system. Although the patent was filed just weeks before the release of the original iPhone, it was not used in the first take on the iPhone. Chances that it has been implemented for the iPhone 3G are slim.
Also in the filing was a description of a portable media device that would keep the original iPod Click Wheel, but would integrated it into a full touch screen.