Hi!
Equinox still manufactures clam shell front wings. Last item of this page:
http://equinoxproducts.co.uk/product...ynes/roadster/
I have a full bodywork from them on my Roadster, and the quality of their work is excellent.
Now, as it looks like you are aiming for a powerful Roadster, I guess you are looking for high performance, so be aware that clam shell wings are awful when it comes to aerodynamics. They are just acting like 2 big parachutes, and will add to the already bad aerodynamics of the car (like all "seven-like" cars, aerodynamics is not the best feature of our Roadsters).
And I'm not even talking about fuel consumption...
But they do look good and no problem on low/mid performance road cars in my humble opinion.
Hope that will help