I agree with you, I think it must be a problem with Windows 7.
In my setup (Samsung Q45 connected via VGA to Samsung 32" LED TV) it was no problem with Vista to get 1920x1080, but with Windows 7 I fail with the same hardware!
In Vista, over VGA a lot of TVs were regocgnized correctly (I was in a big store :-) with name and offered resolutions.
But under Windows 7 on the same computer, the TVs are NOT recognized (I just get "Standard PnP Monitor"), and the max is 1600x1200 that is offered.
I used in both scenarios the newest NVIDIA drivers
Maybe Windows 7 wants to push HDMI technology? I do not understand why. I have three laptops, all only with VGA, so I depend on VGA.