I've just been installing the new Kubuntu KDE4 Remix Beta on an old Acer L100 Media Centre using the Alternative Install CD (so I can do a text mode install) as I only have an old CRT TV attached to it. When I tried to boot from the CD it looked like the installer picked a display mode that didn't work with the TV as the picture lost stability and was unviewable. I couldn't find the usual options to change the screen mode, but found that this worked to override the screen mode: