Xorg problems and resolution

The best resources I found were:
How to create a modeline: http://xtiming.sourceforge.net/cgi-bin/xtiming.pl
Some general tips: http://www.x.org/wiki/FAQVideoModes
A complex example: http://www.mail-archive.com/fedora-list@redhat.com/msg12682.html
Some detailed debugging tips: http://redhatcat.blogspot.com/2007/09/xorg-for-sharp-aquos-and-nvidia-88...

Using the last link, I found that there were three video ports on the card (DVI0, VGA0 and VGA1) and all my settings were being applied to the wrong one.

Here is the first part of redhatcat, on how to do debugging:
Use Ctrl+Alt+F1 to switch to the first virtual terminal.
Login and run telinit 3 to enter runlevel 3.
Start X with startx -- -verbose 6 --logverbose 6 2> /tmp/startx.log
As soon as X displays the screen, press Ctrl+Alt+Backspace to kill X.

Now, we look at /tmp/startx.log. We are looking for the mode validation checking for possible resolutions, specifically 1920x1080. In this output, X tells us that 1920x1080 is to large for DFP, which it isn't because this is a 1080p monitor. We need to tell X to not worry about DFP. Insert the following line in the Device section:

To force the system to use vesa mode, either replace the xorg.conf with something like the xorg.vesa below, or use the command:

system-config-display --reconfig --set-driver=vesa --set-depth=24 --set-resolution=1024x768 --set-videoram=0