At a local informal car meet - cars & coffee - in San Diego there were several 356's being shown and not one was a steel bodied car. There's a local manufacturer of Porsche replicas - Thunder Ranch which perhaps accounts for the number of fiberglass cars on display.
Ekam, not to add fuel to the fire, but here is a link to a Canadian, BC based manufacture of speedsters. They have been around in various forms since the real speedsters were in the showrooms and have some great examples.