He is sweet and even gorgious, really. But I still think he is a domestic, broken mackerel tabby. With tabbies, its not uncommon they do have some spots on tummy and chest. And the broken mackerels especially.
So I dont think he is a descendant from some purebred, but I think its the other way around. It is such cats as he who were choosen to help construct some of the purebreds. For example, to help build up the bengals breed, who are a cross from a small djungle cat, and domestics...