Since you're asking for opinions: First of all I'm not a breeder. Socal brought up a great point about the breeding and making sure the dog was tested for genetic factors. I believe that should be one of the main factors in breeding.
As for the cosmetics... Personally I don't like the look of "leggy" yorkies. I saw one in the petstore window the other day. They just don't look right to me, kind of miss proportioned. It reminds me of a black lab for some reason. Of course I don't know what you're dog looks like, maybe she can pull it off! The colors sound pretty though.
I personally don't agree with breeding "pet quality" yorkies on purpose, especially without papers. I believe that for everyone born one less sheltered one doesn't get a home. There are lots on petfinder and in the shelters that need homes. I believe there is a yorkie for everyone.
I saw that you said that you're a thinking about breeding. I just hope that you know your reasons for breeding, the costs, and I do commend you for going to this site and becoming more knowledgeable on breeding. Just make sure that you've looked into it completely and know the risks and what to do in case something goes wrong and the true costs of it all.
http://www.dogpro.org/index.php?pageID=62 is a great page to see if breeding is for you. I am just telling you this because at one point I thought about it breeding. But then I looked into my Brandy's eyes and I knew that if something wrong happened, I wouldn't be able to live with myself. Also, at Petsmart yesterday I ran into a lady who's dog had to go through surgery because of cancer, which could have been prevented by spraying her.
Good luck with whatever you choose to do. I hope you get all of the information you're looking for. Just make sure you get a digi cam so that we can see pics of the puppies and the momma if you have any!