Growing up in Detroit, at the Detroit Auto Show I'd see show cars built not only by the automakers but by suppliers wanting to show the automakers what they could do. Such as the Mercer Cobra, paid for by the Copper Development Assn. I also vaguely remember a car called the Rohm & Haas Mustang but on the net could only find a drawing http://www.ponysite.de/mustang_rohm_haas.htm Was it only a drawing or did it actually exist? Was it made out of a Shelby? Maybe it was done early enough to inspire the Shelby? According to the description at that website it had a glass roof which I guess you could say inspired a very recent Mustang with a glass roof (which I have seen but don't know if it actually made production). There was also a Rohm & Haas Corvette but I am pretty sure that was an actual show car.
No do not believe it was ever built and can't see any thing that makes me thing of anything related to Shelbys in the drawings
Classic Design Concepts produces a Glass Roof for the 2005 to 2014 Mustangs and for 2009, Ford offers it as an Option on the Mustang. Start checking out the Dealership Lots to see one in person. David.
The text in the link to the sketches that you posted states that the show car is believed to still be in existence. Actually it states that at least one car, possibly the one show car... it's not terribly clear on how many may have been built, but regardless it tells the story as if at least one was built. "Acc. to Mark Gustavson one of these Mustangs - if not the only show car - is still existent today. As soon as we have pics, we are going to publish them here." If you trust information you find on the internet, that is. Based on it being a 1965 concept, I don't see why or how they would have used a Shelby. Presumably the kit would have been in the works as soon as the fastback style came available and waiting for a Shelby would not have been a wise business decision, nor would it help in the promotion of the car since all of the recognizable exterior cues had been changed or removed (color, wheels, hood)
Too early in the Shelby history to tie in with I agree with you, it was too early in the Shelby development to be loaning cars out to be promotional show cars. Even the Mercer Cobra tie in didn't come until '66 or so when the leaf spring Cobra was already out of production, and the Copper Development Assn. had to pay for the car--they weren't given a Cobra for free. Mark previously was involved with a Thunderbird Concept car, finding it and restoring it, and I look forward to what other show cars he finds--he is another on that trail that Joe Bortz of the Blue Seude Shoes collection started, finding derelict concept cars and restoring them. Bortz now has over 20!