I am sure I have seen photos of a red Prince or Knight. I assumed it was done post production. I think it was or is in the USA.
There was also that superb B Rapide engine fitted with red D (naked) cycle parts.
I believe Phillip Vincent had a penchant for red. Wasn't his personal Bristol car red? I can well believe he might have experimented with a red finish for the Victor.
Apart from the completely red B & C Rapides there were some supplied with red tanks and mudguards or just red tanks. There were even blue ones. There were red Comets with white saddles or is all this myth? My first Comet was supplied with a red tank. Perhaps that explains my weakness for red.
Hugo,
I do not know about Phil Vincent's penchant for red. His car was white when I knew him. However, you are correct that there were two-tone Vincents. You could order the bike in red, or you could order it in red/black. In the U.S., where touring fenders were popular, the tank and fenders were red and the rest of the bike was black. If you examine this photo of the Sales Showroom at the Indian Sales Co. you will notice that there are two touring Rapides on the left and one is a red/black bike. This photo was most likely taken in 1952.
David