my windows were cut out when i had the car resprayed, so that they could get right into there and not leave a line.
They had to get someone else in to remove the windows, becuase as said they are sealed in.
BUT saying that, i have seen them out, in, and inbetween and i couldnt see why it wouldnt be possible, i reckon it could be fairly easy with the right parts from a donor car.