When it comes to capacitive touchscreens, we'll lean toward the "bigger is better" end of the spectrum until things start getting too ridiculous. So it's good to hear that the retro-named Chunghwa Picture Tube (CPT) has begun producing 21.5-inch projective capacitive touch panels for validation by clients. The company is also working on 3D panels.
Projective capacitive touch works by laminating a thin grid of wires in-between two layers of glass, and responds to capacitance formed between the fingertip and that grid. That differs from in-cell photo sensing and optical touchscreens, the latter of which has commonly been used in all-in-one multitouch-capable PCs such as HP's TouchSmart range. However CPT do plan to begin shipping such touchscreens in 2010; the company is already shipping 10.1-inch projective capacitive panels.