Touchpad company, Exideas, is using touchpad technology to help build smaller input devices. This one has a lot of wearable tech potential being that, it's so small. I can imagine people using this on their sleeves, as a touchpad "watch" (sans timekeeping), or even on their pants. While I think I would prefer a Twiddler 2 for my dream wearable, this seems like a logical solution for hi-tech phones, mp3 players, and more.
"MessagEase Keyboard uses a system of taps and slides with fewer keys requiring a smaller area. The taps enter frequent letters while slides enter the rest of the characters. MessagEase keyboard is currently available for use with PDA and Tablet PC. A touchpad implementation of MessagEase can also function as a mouse input." [from geekzone]