We have a little Biewer female from Germany! She is adorable! It is true that they are sort of like piebald Yorkie here in the states BUT the Biewers have standards that must be met. They have been bred so that they must look a certain way. There is a huge debate on if a Biewer and a Yorkie should be bred together. There are a few clubs out there that you can look into to even get more information and to find out these standards. There are also shows that the dogs may be entered in here in the US. The following are some links you can check out if your interested!
http://www.biewertalk.com/forums/index.php http://www.biewercoa.org/ http://www.geocities.com/bieweryorkieassociation/ http://www.bytca.org/
BTW I in no way endorse any of the above links...it's only for information!