FYI: Here is the config file as generated by nvidia-xconfig
pastebinit /etc/X11/xorg.conf
http://pastebin.com/f70ababc7
It's what I'm using and it works fine (as long as you don't mind the
image in the center and unused space on both sides).
(... at first, I didn't know about the monitor options for "Full
Screen" and "Native"...)