I think that the Turkish Van, nicknamed the "swimming cat", would be a nice addition to the Super Cat variants. The Cat Fancier's Association has pages dedicated to this unique, naturally-occurring breed.
Some distinct features and characteristics of the Turkish Van are...
- water-repellant fur
- no undercoat, which make the coat feel silky smooth
- primarily white coat with other specific colors on the head, tail, and sometimes random spots on the body; the coat is actually colored with huge patches of white
- a brush-like tail
- blue or amber eyes, sometimes odd-eyed
- top-heavy body with broad shoulders and a forward center of gravity
- fascination with water
I think the simplest way to add the Turkish Van would be to use the Super Persian Cat as a template and then add the patterns and adjust the colors, if not create new assets for the Turkish Van to make it more distinct. I created this quick mock-up in GIMP and used a photo featured on the CFA webpages for sampling colors. I think lighter brownish fur colors and blue eyes colors would be more appealing, but having the Super Turkish Van odd-eyed would be an interesting touch.