I see it as a hobby but also a creative competition with oneself to see just how good one can design and create
Body kits today are tough to design for the simple reason most cars are unibody construction. We do not have cars today being commercially built like they were back in the 70's like the VW bug which had a separate chassis and steel removable body for example. Now if a guy wanted to design essentially a super aerodynamic kitcar that is based on a bug chassis I think that could do very well in fact. There were many kitcars designed around the VW bug chassis. Some were even electric in nature such as the Bradley GTE
All you would need to do is find an old rusted out bug and scrap the rusted steel body and restore the chassis and build your aerodynamic composite or aluminum shell around it. I am doing just this but with a different donor chassis out of a 1970's Triumph GT6. The Chassis of the GT6 only weighs 105lbs so pretty light to start off with. They are hard to come by pretty rare cars here in the US but they share the same platform with the Spitfires which are much more easy to source. The VW bugs are far easier to find and more part sources fro also but have some key drawbacks which is why I did not go with them.