Here is the new Lotus Seven.
The governing idea of the design is performance and fun with practicality. So the convertible top hides behind the seats, but there is still room for a cargo space underneath it (hence the large behind). The small grill up front is to allow the small turbocharged engine to breath while maintaining a good drag coefficient, which is important to keep the car's fuel economy on par with those of compact 4 doors, despite the added performance. The number of seats, however, remains at two.
I'm not entirely happy with the design. On second viewing, It looks a bit too old and I'd add a bit of sharpness and edge to it. But since I'm out of time this will do and I still love how it looks. As a Miata driver I should be able to come up with a good british roadster concept but let's see how I did!
Also, I couldn't quite resolve the rear end but that's the general idea in the rough sketch. Tall with round tail lights. The inspiration for the design was the Jaguar F type concept which is one of the most beautiful cars never made.