I have already purchased the CG Ferrari 512 chassis, R/M stock car chassis and a Lola T-70 chassis from another maker with Shapeways and am happy with all three. Here are a few more I would like to see someone design and produce.
Fly Lister Storm
Fly Corvette C-5R
Scaley Corvette C-6R
R/M Daytona Cobra
Flyslot Kremer CK5