With the hack in place, I decided to update my program to be able to write pngs to the display. With a little mplayer-magic in place, I got this result. The movie is streamed over USB, the sound comes from the PC. The framerate is about 8fps.
I have packed together the program and firmware-hack together in an easy-to-use package for Linux-machines. Download it here. Instructions are contained in the README-file, and I'd appreciate a mail if it works for you. Please note that the software can't modify the pictures stored on the device yet, perhaps I'll add that when I have the time.