I have been told this by a fellow Cardinal flyer that used his plane to take pictures, but have yet to try it,
If you get some black foam rubber make a cone that fits on your lense, you can place the foam rubber against the canopy, the foam will block light from the inside of the canopy but allow you to shoot through the canopy with out any reflections and keeps the camera from scratching the canopy. Sound like it will work, just have not found the stuff or the time to attempt it.