About four or five years ago, I was working at a body shop in Minnesota. It was spring and I was jealous of other people's convertibles—so I made my own out of a Jeep Grand Cherokee. Jeep's aren't supposed to have roofs anyways.
The new Fiat 500C comes without a roof. This design is much better than convertibles because you need sides for aerodynamics not necessarily roofs. Sides are key and you want to see the sky so all you have to remove is the roof.
I sold this Jeep a few years ago because I did not have a place to park it. LA city parking attendants were sizing it up to see if it was abandoned. I drove this Jeep (see link) from Minnesota to Florida while I was teaching and driving a school bus there (you don't need a teaching certificate since some areas are like third world countries).
Much of the time it was weighted to the bump stops with tools. I also drove it off road in the forest and in the sand. It creaked a little but nothing ever popped. I wanted to roll the Jeep down a big hill to see where it needed some sheet metal or aluminum tubing reinforcements. I wanted to put a diesel in it. The same one that came in the Liberty.
The de-roofing modification started as a sunroof but soon after picking at it a little I saw there was no major structure. That Jeep was awesome and light with no glass windows except the windshield. Loved the solid axles. Didn't like the automatic transmission or gas engine (although 4.0L was OK). It could take rain, snow, and 110 mph speeds without the soft top or windows I fashioned flapping. My soft top took
about 1/2 hour to put on and it came completely off. The side windows were made of plexi glass and vinyl fabric. The front ones were removable. They just slid in the original glass tracks and were secured with a screw. Fortunately for me I never crashed this vehicle, but if I had we could have got some crash test data.
Fiat I know you saw me driving around Beverly Hills with Minnesota plates looking like a modern Beverly Hill billy. I got more looks than people driving in limos or whatever they like to ride in. Please send me a check or MultAir variable valve diesel engines. :)