Two seater Mustang convertible prototype?

I was looking at a Mustang history the other day and it had two shots of a 1965 style Mustang convertible, white, that was a two seater. Now I have seen the two plus two coupe cut into a two seater by Andy Hotten both in person (at Green field Village) and in pictures but never seen this convertible before. Did it get to the real metal stage or only a clay model? I wonder if Shelby ever looked at it and thought of offering it as a Shelby? The timeline would have been around 1964. At that stage Ford was already starting on preparing Mustang notchbacks for racing in Europe so I would have thought a two seater would have been considered. I would attempt to show the photos but first I have to remember which book and as I remember they were very grainy.

Also somewhat related, there was a mid-engined show car called the Mach II or maybe Mach 2. I can swear I saw a picture of it once fitted out with racing stripes and Shelby nametag but never been able to find that picture since which means I could have imagined it. I also heard Alan Moffett from Australia prepared one for racing, which would mean there was more than the one driven around by the Motor Trend writer. It was around '66 I think.