You could have a set of Billet caps made ( we made some at my previous employer , for some cars being built in our area ). Trust me by the time you have someone model them up (3D) and the machine them, you can buy another set of wheels. In the 3 sets we made we had about $400.00 in each cap ! It can be done though. We made a lot of parts for these 2 cars.
http://elec-mech-tech.com/specialty.html