Don't get me wrong, personally I think it would be fun if prototypes and cars that didn't make production yet were included here anyway, but it needs to be one way or the other. Cars where only one was produced have been questioned before, let alone none at all. That said, that's a pretty cool car I might not have ever learned about otherwise. IMHO either the car must have made production and a minimum number is defined, or we allow prototypes, concepts and cars that are planned for production, or even one-offs (my preference)
I know that could be open to misuse but common sense should prevail, it should be a photo of a complete body at least, and often it will be obvious that it's in a show setting, giving us an additional clue. If the car is a little obscure, the poster needs to be a little more forthcoming with clues.
There have been tons of cars which will probably or hopefully be produced, then aren't, especially supercars, so that seems a little too vague to me.
