Breeding 2 different kinds of dogs is not like breeding 2 different kinds of ball pythons. With 2 diff morphs of ball pythons, you have to remember that the only main differences are the colors and pattern of the snake. There arent any physical differences like size and shape of the animal. With dogs, they are all different sizes and shapes. In some cases it isnt even safe to breed 2 dogs together, or even physically possible (imagine a male great dane and a female chuhuahua for example) Even though some consider all dogs the same species, they have evolved to so many different breeds that it doesnt make sense to say a dog is a dog and all can/should be mixed. Would you say the same about snakes? Is a snake a snake? Going even more specific, is a python a python? Of course you can get diff kinds of pythons to breed just like you can get different kinds of dogs to breed but why would you want to mix them together when it is recognized by most serious breeders/owners as a mutt?