More power to ya tgrlily. Yeah if the goal is to make a pretty bird, there are alot of gorgeous mutt birds. EE's are a very accepted & diversely colored line of mutt chickens. Again, I hope I am not offending anyone, it just seems in the last three days I read, here on BYC, the same thing about 5 or 6 times. Someone wants to create a NEW variety of chicken. It appears like alot of people have great ideas for new colors. Some here are just trying to keep the existing varieties healthy.
It would be cheaper, easier to just import birds from the UK. Pay the Customs, quarritine all that stuff then rasing a dozen generations of Orpingtons. And you may never achieve your goal by then either. And you should be prepared to breed ALOT of birds to get the same end result. OR you will just create a very small gene pool for all to play with as your project.
Any way you do it tgrlily, you better have a deep wallet. Even to be worth the time, your NEW breed of Orpington will have to meet a standard to be shown. Right now in the USA there are Black, Buff, Blue and White as recognized varieties Orpingtons.