Sighthounds are whippet, greyhound, afghan, saluki and all those types. They hunt by sight so tend to be slim and athletic in build. Hounds that hunt by scent are usually a bit more bulky!
Becky
My money would still be on whippet x SBT, its a common cross and you do get some that have a more whippet head. It might not be a straight 50/50 cross though.