I thought Chai was a Parti?
They are beautiful, just like Tri and Chocolate. And just like them they are not the breed standard and not something that breeders of Standard Yorkies are trying to achieve.
Just like your tiny (and mine) I would suggest finding one that is a result of standard breeding. Most information I have found says they should not be used for breeding. I have been told they can be AKC registered if their parents are standard but it's tricky since that color is not listed on the registration of Yorkshire Terrier.
If you want one, do your research. Read the YTCA website opinion
www.ytca.org (go to FAQ)