Gnome in the context of multiple screens

The current model for multiple screens is that of a screen wall. A second screen is assumed to sit in relation to a first screen and is considered a visual extension of that screen. But that isn't how many people use their second screen. Instead they see it as a separate workspace which they interact with independently from the other screen.

So what I am proposing is some way to allow gnome to treat a second screen as a separate workspace with its own taskbars, etc. So that when you change virtual workspace on one screen, it doesn't switch the other physical screen. One would still have the concept of positional relationship which would control how one drags windows between the physical screens.

Which virtual space a window is in would be based on which virtual space the cursor is in. Also virtual space controlling keys like ctrl-alt-arrows would follow the mouse. Naturally this mode of operation would be optional somehow.