Not just success... very good success.
On debian running latest kernel 2.6.31, using the soft-link header trick courtesy of Rebecca:
where you substitute 2.6.31-1-686 or whatever for your linux-headers version works beautifully, allowing clean compilation with 2.6.31. Of note, the compiled kernel will still be in the src/2.6.28/ directory.
$ cd /usr/src/linux-headers-2.6.30-2-amd64/include/linux/
$ ln -s /usr/src/linux-headers-2.6.30-2-common/include/linux/input.h
$ ln -s /usr/src/linux-headers-2.6.30-2-common/include/linux/input-polldev.h
$ ./configure --enable-wacom --with-kernel=/usr/src/linux-headers-2.6.30-2-amd64
Ayuthia's latest patch eliminates the weird pixel-jump behavior. Coming along beautifully!
P.S. On modern debian, the hardcoding and avoiding of /dev/input/mice is NOT necessary. I switched back to /dev/input/mice for the core pointer, as this allows simultaneous use of my pointing stick on thinkpad, a separate desktop USB mouse, AND the wacom device.
P.P.S. I am a researching cardiologist, and just used my new tablet to draw a figure for a paper in inkscape. You guys are doing great work with open-source support of hardware so quickly and I am very appreciative. Kudos!