Yeah, Windows isn't exactly good about the separation of church and state...err, I mean driver and window manager. If this is possible, what I think you're going to want to do is configure the driver so that it reports two separate screens, and then tell Gnome that you want the task bar to span both screens. I'm afraid I don't use Gnome though so I can't tell you where that option would be or even if it exists.
Actually, I take that back. Google suggests that it can't be done.
The suggestion there is to have two Gnome panels and put one on the second screen. I don't know if that accomplishes what you want, but it would work.