EDIT: Sorry I got it working on the desktop but when I try games the res isn't there...... even if you manually add it to .ini files it doesn't work :(
I have plugged in an extra HDD and installed XP on it so I can play Far Cry 2 @ 5040 (mmmmm Ultra High settings at about 45-60 FPS) using the latest drivers. So I thought I would see if you can get 1920x1200 and you can using NV custom res.
So use Cranky's excellent
tutorial (now slightly out of date but I'll point out the differences):
1st: De-select Force HD Resolutions and select Allow modes not exposed by the displays (Cranky's 1st image).
2nd: You wont have to select adaptor (3rd image) in Front end parameters, that info will be there and greyed out.
3rd: The stuff in the advanced section is different but the same stuff needs to be changed. Make sure refresh is 60 rather than 57, the polarities are both minus etc.
Now I have XP with 1920x1200 so it is bye bye Vista (and TRI SLI :( but I'll put my 3rd 280 in my other rig for better folding and put the 8800GTX from that into this one as the PhysiX card)
EDIT: whoops in the first image you still have to put 1920x1200 in the Active Hor Pixels and Active vert lines boxes, took the screeny to early ;)
(Admin Edit: I fixed the URL link, and edited the pics to take out the white space - Ibrin)Edit: Thanks my editing skills suck!