Just got my new plates for the Citicar in the mail.
Like the Electric Motorcycle, they are Hobbyist plates. Hobbyist plates are similar to collector plates, only they are for homebuilt, modified, and hotrod vehicles.
They are "permanent plates" in that you don't have to pay an annual renewal. The downside is that they cost double to get, and you can't drive the vehicle in January. (Although there is a temp pass you can get in case you have to go to a car show in January, for example)
I originally thought the number would be the same as is on the motorcycle, but with an "A" added. Hobbyist plate-holders each get their own, personal number. Oddly, the number is different between cycles and cars!