A few days ago I finally gave in to the two-for-one tablet deal at geeks.com. On a side note, I've always had very good luck with geeks.com, good stuff, right price, no problems. Anyway, I gave in and bought myself two of the DigiPro 5.5"x4" drawing tablets, Model No. WP5540. I tried to find some compatability information about the tablet and linux, but couldn't.
I got it yesterday, hooked it up and its working just fine. I don't know about the "512 Pressure Levels", since I'm not sure what app on my machine would take pressure levels anyway. The GIMP didn't seem to act any different however. I did uncomment the information for a wacom tablet in my xorg.conf and restarted my X server, but I haven't tried it without that change, so it may not be necessary.
5.5"x4" is about as small as it sounds, but it really isn't that big of a deal. There is plenty of fine control on the tablet, and it's more than big enough for me. I intend to use it when I'm working in the gimp, for fine control of the lasso tool, etc. If it had a scroll wheel on it, I think I'd replace my mouse, it's that comfy. Plus you can roll the pen between fingers and type just fine. No more grabbing the mouse every few seconds.
For the record I'm on Mepis, whatever is current there, with kernel 2.6.15-26-386.