Pipe Novelist, I disagree with your "time to mature" theory. Penzance, and all other Jersey tobaccos, go in and out of the door very quickly.
To the OP, try some H&H Ten to Midnight, a close flavor approximation that is readily available. On a sad side note, it wasn't too long ago that you could buy Penzance, Special Latakia Flake, Krumble Kake, SH Anniversary, Exotique, and Our Best Blend very easily. All shared the Germain DNA and spirit.