As long as there are "cull buyers" there will be "cull sellers" and as long as there are dogs raised there will be culls out there. Best bet buy puppies from long standing good strains of dogs and hope for the best, older dogs try them and see if they fit you. Big boys don't cry if they get beat.
5 years ago I decided to switch from cur-crosses to all plotts! I made the commitment to go with puppies from respectable bloodlines and breeders and it was the smartest thing I ever done. The truth is if a guy has very high standards the dogs he's looking for will not be for sale anyway so the puppy route is actually your only option, just buy plenty because most won't make the cut. Lol