Looking for a small dog to add to family

My name is Jennifer. I'm 31, married, living in Wisconsin. My husband and I foster for multiple local shelters and rescues. We've transported cats and dogs from different states. We've done foster-facilitated-adoptions for many of our charges. We have 4 kitties and 4 Chihuahuas. We recently lost our 15 year old and I feel it's time to consider filling the hole he left. I'd love to welcome another Chihuahua, Pomeranian, Min Pin, or some other little breed, and would prefer an adult to senior. I'm willing to travel provided that the circumstances are right. :) Thank you!