Wolfgang,
You seem to be saying that it was legal in the past to register a replica in California as the VW from which the pan/VIN # was taken. That's incorrect. CVC Sec. 580 is the statute on point, stating that a SPCN vehicle no longer resembles the donor car, and it was enacted in 1983. Thus, registering a replica as the donor vehicle which it no longer resembles has been illegal for the last 35 years. Perhaps I miscontrued your post.
My research indicates the 500 SPCN registrations/year has been more than enough for the last few years.