i realize this thread is already a few weeks old but nevertheless this might be interesting for users with the same problem as well as for nvidia developers:
i while back i came across the same problem as user lblume describes above with driver-version 100.14.11. after searching for quite some time i found that there are others who have the same issues with 1600x1200 resolution and after some further research and trying around many hours i came to a solution on how to fix the matter. everything is described in this long thread
here which i kind of hijacked but which also brought me a lot closer to the source that might cause this problem. its quite a lot to read but i guess the central aspects are to be found in my posting #58
i also translated my description into german and posted it on hwluxx-forums in a lengthy thread about my motherboard with nvidia 7050 onboard graphics chipset
in postings #337
there seem to be not too many users which run a combination of a 100.14.xx - driver at dvi-port and a resolution of 1600x1200 since i could not find much about this issue around the web and i thought that this might have been fixed already but when installing ubuntu 7.10 which comes with the 100.14.19 driver i realized that this behaviour is in fact still there. luckily my fix still worked ...
i didn't get much feedback from other users that have the same issue since its quite some effort to get this fixed but i think it should work for almost everybody.
so hopefully this bug won't be around with further releases since from what i've seen this seems to be a bug in the drivers interpretation of the edid submitted over dvi by the display.
EDIT: omg, i've just seen that this thread is posted in the solaris section! (found it via the boards search)
but i haven't found any threads coming closer the the issue than this in the board even though i am talking about linux not (only) with focus on the BSD-branch here...
EDIT2: ok, i've now just seen that there are also threads in the linux-section which reference this topic! i'm sorry to have not seen these earlier but since they (as far as i could see) don't come up with a general solution i will link this thread in the ones i've found adressing the same problem...
EDID resolution problem
Cannot get native resolution
oh, and sorry for the confusion!