Hello there.
I've been using a graphic tablet instead of the mouse for years now. Graphic tablets always have some control problems with (mostly) 3D interfaces if the software does not provide a "tablet mode" in its preferences. This is due to the absolute pointing behavior. Many 3D applications (Rhino, Softimage, Poser etc.) include a "tablet mode" switch in preferences to allow correct panning and 3D movement. I didn't find anything in SL at the moment, this would be a dramatic enhancement for every tablet user, because 3D editing is much more powerful with a pen than a mouse.
Thanks very much for your time, any feedback is really appreciated.