The Resize and Rotate extension in the new Xfree86 4.3 should let people dynamically change their screen resolutions. From what I understand, KDE 3.1 anticipated this and already has the ability to use this feature in X 4.3. Since the next release of Knoppix will include KDE 3.1, it will hopefully be only a mater of time until X 4.3 makes it's way in.