Apparently Compaq has also been doing research on a Linux-based PDA! Here is a link (which I noticed on http://www.tech-report.com):

http://computer.org/computer/homepag..._pract/cp1.htm

I didn't read the article really, but it seems that they're experimenting with both voice and gesture recognition (like tilting the thing) as input methods. There are some pictures of a sample unit, which IMHO is ****-ugly.