If you go to the Detroit auto show...

there is supposed to be a glass roof Mustang a prototype of what will be offered in production. If the Ford brass is there ( probably will be only at the Press days) maybe you can put a bug in their ear about making this available as a special Shelby model or available on Shelby models. I remember dimly that Ford offered this on a car called the Sunliner back in the Fifties. It would be very uncomfortable unless they have a way to cover it up from underneath on a hot day but would be great for the Midwest in autumn, winter and spring. I remember driving a Porsche that they called the targa but which actually had a glass roof that retracted down atop the fixed rear window. Ford's is not retractable. There is already pictures of it on the net though the show isn't until January