i dont know about crossing them out but i know a lot of other breeders do as well. one of the breeders i frequent often also does this with 2 diffrent lines that produce some good looking ghosts but none in my mind match the butterscotch. the sharp line that Jon aka coldbloodaddict works with come straight from sharp who got a group of wildcaught hypos that is now known as the butterscotch line compatable with all others ( except a few that the others are not able to too)