[teeedubb]

From a quick look at fritsch's guide you can change the upstart script to load fluxbox I stead of XBMC, so it should be possible. You could probably install open box and change the upstart script to load that instead. If you want to use fluxbox you'll need to skip the bits about enabling openbox, setting it as the default session and alter the lines that add commands to the open box autostart.sh file to point to the fluxbox autostart file (not sure if fluxbox has one though).