First post in a very long time, but this is an issue that's near and dear to my heart.
If you're looking for a small dog, there are literally hundreds of local societies dedicated to saving specific breeds from the high-kill shelters in California. My girlfriend has been looking at them for a while now, and they're definitely the way to go. There are tens of thousands of dogs just waiting to go to the gas chamber down there, so all you need to do is locate the local society responsible for that breed and tell them what you're looking for. They take care of all the rest. A lot of them know one another, so chances are one can point you to another, if they themselves can't help.
And since we're talking about small dogs, I may as well lighten things up a bit:
Small dogs wearing things