I would read the Yorkshire Terrier Club of America's Code of Ethics and Conduct -
http://www.ytca.org/frame_index2.html
It does state under the code of conduct section (number 4) that :
Puppies will not be sold or consigned to pet stores, agents, or other commercial enterprises nor sold to disreputable breeders, and neither puppies nor stud services will be offered as prizes or for raffles.
I would consider a broker a "commercial enterprise" so according to the YTCA a breeder should not sell a puppy to a broker. You may disagree. However, as a breeder I subscribe to this standard.
If I ever had a situation where for whatever reason (emergency situation - hospital stay, etc), I need to place a puppy quickly and I do not have a buyer at my price ($2k male/female regardless of size), I would GIVE the puppy to a good home for free before I sell to a pet store or broker.
I'm not saying that the broker you state is bad, but I wonder how they can be sure of the history of the puppies they purchase especially if they are from out of the country - genetic defects, living/breeding conditions, etc. They might be taken care of once they reach the broker but brokers (again not saying this particular one) are part of the problem (along with pet stores) that keep puppy mills in business.
I live in PA about an hour east of Lancaster. As many people know Lancaster is puppy mill central. The Amish are famous for their way of life and also infamous for their puppy mills. Its a sad situation.
Good luck in your search.
Terrance Ferragame