Dan, I don't know how thoroughly your state checks these things out but what about having a replica plate made from one of the companies that makes them?
A friend here in Georgia had a 1958 Georgia plate made for his Cadillac - 586239. This signifies a 1958 Cadillac series 6239.
They do not attempt to verify that it's a real YOM plate (how could they?). You just have to show them the plate and as long as the numbers aren't in use, and it's the right color, etc, they'll grant you permission to place it on your car and issue you a modern plate to keep in the glove box or whatever.
Of course don't tell them it's a replica.
