the reason I asked is I was wondering what look you were looking for. Here is my take on small designer mixed breeds as I have one. Lola is yorkie pom and I had four purebred yorkies before her. You may have seen one that you fell in love with but that does not mean the one you get will look anything like what you saw. I realize that can happen with purebreds but not nearly as much or as wide of a swing. Every yorkie po I have seen are different, my neighbor has two and they are supposed to be from the same parents about a year and a half apart, one is all white the other all black, I would be hard pressed to see any yorkie in them and they are about 15 lbs Another friend was taking care of one for a while and it looked more like a yorkie but bigger with floppy ears. I saw one in the park yesterday, he looked almost like a dark curly small maltese. Each one was cute but different in size and color. My friend that has two even though she lovers her dogs is a bit disappointed in size and that she can't see any yorkie in them. Each time I see a yorkie pom they also look different, case in point, look at this facebook page of a yorkie pom, then look at some of my albums on here, to me both dogs look nothing alike
https://www.facebook.com/#!/zoey.bear.14 Breeding mixed breeds aside from the crap shoot on health issue is also a crap shoot on appearance. My advice for you is to find one that is at least 3 months or older then you will have a bit of an idea of what the puppy will look like full grown. Lola was 4 months when I got her, so I could tell she favored more of the yorkie side, especially her color markings, while her brother was smaller and a little ball of 100% chocolate fur, I am assuming he wound up looking much more like a pom. Good luck I am sure whatever puppy you wind up with, will be well loved.