I've been to far too many pounds and shelters over the years...where do you think my beautiful Rottie cross came from. There are as I said...plenty of Dobe crosses and even pure Dobes in pounds and shelters...like on Pet Rescue...you just have to look.
Your aim is to breed more cross breed dogs and you just can't see this is wrong in so many ways. My Dobe was main register but that didn't stop her getting Wobbler Sydrome (might want to look that up)...imagine if I had bred her...she would have passed in on to the pups and there's no test for it either. So if my girl had that...what health or temperament problems are hiding in your dogs genes...you don't know what you'll get and that's a fact as your just another backyard breeder.
Because I've had problems with Registered Breeders as many other people have... doesn't give me the right to breed my own. There are so many dogs in pounds and shelters longing for a home to be loved and guess who's going to add to that problem.
You might want to look at these.
Companion animals—a cherished part of Australian life // Animals Australia
Animal advocates issue warning on buying from backyard breeders | The Advertiser - Cessnock
10 reasons why you shouldn’t buy from pet shops or backyard breeders - Roka Pet Photography