You can't develop a "breed" until it breeds true. All of the birds in the APA SOP were accepted to a breed standard, and that breed standard is different for each different breed in specifics such as tail set, carriage, egg color, feather type and color, clean or feathered shanks.
You can create crossbreeds now, as I am doing with my flock. My goal is to produce a good laying dual purpose fowl with a range of egg colors. The hens are ISA Brown red sex link light fowl, there are two roosters, an Ameraucana/Salmon Faverolle cross and an Ameraucana/Light Brahma cross. Both roosters hatched from green eggs.
The hens produced from the Salmon Faverolle based cross will be bred to the most superior flesh and conformation Light Brahma cross. Light Brahmas are very poor layers and very slow maturing birds. This will be a dual hybrid cross with the goals of creating a rainbow of egg colors and a moderately fast developing, large, good laying flock.
Since I am not selecting for color, but instead for egg production, I will be selecting for productivity rather than for a conformation and color. Over several generations, I expect the offspring to become somewhat standardized, and at that time I can choose to selectively breed for flock color. Right now I have pink, yellow, and green shanks; clean and feathered shanks and feet; short and wide birds and slim, narrow birds. I have white with black, black with white, partridge colors, buff, white with buff, and jubilee/cuckoo colors. All these out of the gene pool that makes up "ISA Brown" and a couple of crossbred roosters.
Concentrate on the traits you desire most, and develop from there. Your dual purpose birds may have some individuals (in a same age flock) that consistently lay larger eggs, darker eggs, or more eggs. You will need to balance these, as more eggs leads to less dark eggs, and large eggs lead to fewer eggs, and darker eggs are a result of fewer eggs. You can also encourage or discourage additional pigment freckles by selective breeding. Many of my customers like them, even though they are a "fault".
I know you are looking only for scientific treatises, but since you are not breeding to an existing standard, most of the work will be careful selection on your part.
And I too need winter hardiness, so my birds are rose or pea comb.