I have just posted on gitorious.org my latest pet project - gimpsketchbook - a set of python scripts that allows you to use gimp as a sketchbook (evidently :) ).
It consists in an external GUI app and a Gimp plugin. The plugin starts a D-Bus server and executes certain commands sent by the GUI. The GUI stores your settings from one session to the other and acts as a D-Bus client.
The idea behind gimpsketchbook is to have as little (no) need for a keyboard, so that working with Gimp while in tablet mode (when the keyboard is tucked away under your screen) is not as difficult as it is now.
Tested and developed on Debian and Ubuntu. Requires a fairly new PyGTK.