You made a good point Ben about the shortage of entries in CKC and AKC events.
The CKC is working on including mixed breeds in their Obedience events.
The AKC has gone a step farther:
"There are many special benefits to owning a purebred. At the top of the list are matters of predictability and reliability.Purebred dogs are the result of a long process of selective breeding for specific physical attributes and temperaments. When you buy a purebred puppy you know what to expect as far as size, amount and type of coat, and temperament in the grown dog.
When considering a purebred dog it is possible to narrow down the choices to those that most clearly fit your personal lifestyle and interests. For example, will the dog be good with children? Will you have the time to groom and exercise the dog properly? If you buy a dog with qualities you want it's more likely you'll be a responsible owner.
A good purebred breeder will tell you why his or her breed is not for everyone and help guide you to a breed more suited to your lifestyle. These breeders also have the experience to give puppies the care and nurturing they need at critical early stages. This not only insures you'll have a healthy puppy, but that the puppy is much less likely to develop into a difficult or impossible adult.
As an advocate for all dogs and dog owners, AKC will launch a special Mixed Breed Listing program in the fall of 2009. This service will allow owners of mixed breeds participate in standalone AKC Agility, Obedience, and Rally trials. " quote AKC