I realize this is an ANCIENT thread, but I post this reply for people with the same problem I had who may find this thread. My issue was using Sabayon (though not OS specific) Linux with a Polaroid tla-01911c 19-inch HD television as a monitor attached via VGA cable to my nVidia GeForce 6200 NV44a AGP video card and not getting the proper set of resolutions available to the "monitor". Studying my /etc/var/Xorg.0.log showed me that the card could not get EDID info from the monitor. (Let's see how many more keywords I can add)
What I finally did was set a "modeline" (not just "modes" but actually "modeline") so that EDID info was not necessary. Turns out it's an ancient method that still works.
The link below is what got it working for me:
Hope this helps the next poor fellow looking to get something other than 4:3 resolutions on a 16:10 screen!