I had an enclosure made up when I lived up in Grand Rapids...they added zippers to my bimini and built a canvas enclosure around the cockpit..windscreen and side curtins are made out of plastic and it has screens for when you roll the side curtins down. The back slopes down to the transom and is solid. All made out of Sunbrella. Looks and works great.
The guy who did it is in Fruit port. Canvass Creations 616 865-1453. Total cost with my bimini was about $1450