This CNet article details Sony's withdrawl of it's Pen Tablet computer from the marketplace:
Slow sales are leading Sony Electronics, the PC division of the Japanese electronics giant, to rapidly phase out one of its more glamorous product lines--the Vaio Slimtop Pen Tablet--the company has confirmed. The computer came with a touch screen that allowed people to draw images directly onto the monitor and run Windows applications with a stylus.
Just an indication of the marketplace interest in such a device... especially for those of us who would want Apple to create a similar form-factor device.