Richard,
My wing was made by Alfa Fibreglass it's a copy of a V8 Supercar VP Commodore wing, they make it to your spec, ie. where you want the mounts and width.
I had mine made to the full width which is 160cm, the wing cord is 27cm. They can also supply the end plates if you wish. The price was about $500.
If you want I can help you contact the person that made my supports, I'm sure he would still have the drawings I did for him.
I would steer away from the Ebay specials as most only create drag with very little down force, also you can be sure the V8 Supercar wing makes real down force and I can vouch for that.