I am in the process of hooking up a system so I can see my back swing.
I will use my Hi 8 camera on a tripod behind me. Use a long S Video cable and hook the out put of the camera to a 19 inch TV which will be right in front of me, or the direction of my eye sight will be at set up.
With out a ball and for practice only, as I take my club away I will actually see and sense my alignments...........No illusions!!!!!
A great way to practice, at my facility we have a monitor sunk into the ground, face on to the player if you like, we can draw plane lines onto the screen so as to give the player a real feel to their backswing, they can see and do at the same time.