Problem with this is that bed rationing is seen by many as unethical. Plus there are gray zones, you're putting young people in horrible moral conundrums on a day to day basis.
Temple Grandin had some interesting thoughts on how single trait breeding can lead to adverse affects in her discussion on "Rapist Roosters", and how this relates to software[0]. It seems like this is also happening here.
Typically when single trait breeding leads to an adverse, undesirable affect (lack of taste), while the selected trait was obtained (in this case, possibly bigger size) breeders don't start from scratch by trying to isolate the desired trait without obtaining the undesirable trait. Instead, as in software, the breeders iterate by trying to remove the negative trait, complicating the hybrids and possibly more unknown adverse traits. It seems like it might be wise to start from scratch in some cases and keep it simple, rather then make hybrid species whose lineage can be difficult to trace.
That explains why most every dog breed that competes on looks and becomes popular gets messed up. Also American breeders have this odd habit of taking large dogs that should be about 80 lbs and breeding them into behemoths, usually to the detriment of the dogs
You are being too nice calling it a habit. Breeding behemoths is what sells. People will pay a premium for the pick of the litter (which is code words for "the biggest"). I don't have any problems with dog breeding per se, but the market forces are seriously broken.
EDIT: In addition to pushing for bigger dogs, it's also profitable to drive down food and vet costs. Kennel clubs like the American Kennel Club are scams. The kennel clubs just receive fees for processing paper. They don't inspect breeders. They don't care if you're a puppy mill. As long as you pay your fees, you will get your papers.
the puppy mill thing is disgusting. I also knew a pathologist who clued me in on the fact that a lot of the breed characteristics are considered diseases in humans, e.g. the achondroplasia of dachsands and basset hounds.
My thinking- you should breed for performance, health and temperament.
Russians did this with the German Giant Schnauzer and created the Black Russian Terrier. Their Giants are also significantly larger than the ones with German heritage, but both are recognized as the same breed.
