If you remove the inside window frame from the door you should be able to do what Phil said and go between the glass frame and the weatherstripping. You may even be able to access a little bit of the frame top and lightly pry down the window frame while gently working the regulator. If you can get a little clearance you may be able to slip a nylon tie wrap over the window frame to the other side. If you can somehow do that you could use the tie wrap like a saw and break the window frame away from the weatherstripping while gently working the regulator. The line used in weed eaters might also work if you can get a little bit clearance. The front of the window might be a good place to work with because it goes down first.

Ed