Comment 21 for bug 86072

(In reply to comment #12)
> After rebuilding the 'xorg-x11-drv-ati-6.7.194-2.fc8' driver package on an
> otherwise up to date 'Fedora rawhide' system, the X server starts up correctly
> which means that the main issue has gone away. However, the X server now
> ignores the 1400x1050 mode entry in xorg.xonf and defaults to 1280x1024 at 85Hz
> which it didn't do before.

Can you attach your xorg log? I suspect your monitor doesn't have a mode in the edid for 1400x1050. The edid's preferred mode is probably 1280x1024@85, that's why it's getting set to that by default. you can manually add the 1400x1050 mode:
xrandr --newmode <1400x1050 modeline>
xrandr --addmode VGA-0 <1400x1050 mode name>

At the moment I only add the screen modes to the LVDS output (and even then I probably shouldn't). The problem is, with randr, which output to you want the screen modes added to? You may not want them on all outputs. You should be able to add a monitor section for each output and add the modes you want there, but I'm not sure the server adds them properly (I need to double check that).

Finally, can you attach the backtrace from the new VT switch crash?