Re: nvidia-settings only allowing 1440x900 resolution
What you need to use to specify other resolutions are MetaModes, but off the top of my head, I can't recall specifically the note that described it, but it bit me too, and was in the first 302.xx release, if my memory serves me correctly. Things have gotten a lot better since then, though, since on 302.17, there wasn't much you could do to work around it - MetaModes were a tad whacked as well . . .