I just have to say, you aren't doing yourself any favors comparing your horse breeding goals to the designer dog craze. Anybody with any common sense knows those breeders that mix up mutts and slap a fancy label on them are interested in one thing and one thing only...dollar signs. 90% of these so-called "designer dogs" would have been sitting in a box at the flea market with a big FREE PUPPY sign on it not so very many years ago, until somebody figured out that a new fancy name was enough to con ignorant people out of stupid amounts of money. Breeding horses, and doing it properly, should not even be in the same category as that mess.
"Keep a leg on each side and your mind in the middle"