The dark coloring that you have described does not meet the Yorkie standard, which calls for a steel blue coat. Breeders who are trying to produce pups that meet the standard will not be breeding for that color combo. For that reason, you *may* run into some problems finding one that fits that description, and even more of a problem finding a dog that does not meet standards that a breeder will place with breeding rights.
Nevertheless, welcome to YT!