I'd guess that you'd have a lot harder time finding a someone responsibly breeding whites. I could be way off base here but if someone's intentionally breeding for DQing faults (and breeding for color), isn't that a pretty huge red flag? That makes me wonder what other parts of the standard they're choosing to ignore.
Not that I can talk, my dog's unfortunately oversized as ****
And going for a black Vs white is a huge difference. Blacks can pop up in byb and American lines but for the most part you would find a responsible working line breeder that may have black puppies pop up often. Whites are not going to come from working lines. So it very much depends on what your going for temperament and drive wise.