I like Slieghty's proposal. Its straight forward and simple. Nobody said for engineering to stop like some people suggested. This idea was to put a cap on the retail value or street price of chasis for this class.
Like Slieghty stated each manufacturer can submit a chasis for approval.
Heck if some one can produce a carbon fiber twin deck with alluminum bulk heads then it should be allowed if it falls within the set price.