I'd really like this too... being able to 'create' a 5th window (undocked) which can hold the perspective view, probably on another monitor. That way, the 3 CAD views (top, section and front) along with the Properties windows can stay exactly as they are, docked inside the main CP screen.
But then, if we could have an option to just create views as we need them (as many as we need) fully undocked, then that would be even better.
Ian