Ramona, maybe you should have read those DVI specs yourself as well. If you read carefully you can find that it DOES support 10-bit signals. Always has 🙂
Although I must admit that it’s also clear from the specs that no official ‘standard’ has been developed as to what a 10-bit DVI signal should look like. So it is possible, as long as the video card and monitor play nicely together.
I’m saying all of this from the top of my head, but I think there was also some kind of bandwidth limitation when using 10-bit so I’m not sure up to what resolution you could go.