Convertible Speaker locations

I've been toying with the idea of making a drop-in speaker tray for the top-well that I can utilize the bracket across the back seat and just hook them up and lay them in when the top is up. Maybe could possibly build them to also sit up a little higer so they can sit on the top when it is down.

Any have any unique ways that that you mounted 6x9's or other decent speakers in the back of your cars without cutting the fiberglass side panels?