Maybe you all can help me solve the mystery that is my dog

She was adopted from the shelter and we have absolutely no idea where she came from...breed or home wise.
My best theory is either Australian sheppard or boarder collie mixed with corgi or maybe even some type of small spaniel (or maybe just a plain old mutt). She certainly acts like a herding dog! Here are a few pics: note, she was freshley groomed in both, the fur on her ears, legs and belly actually grows a little long.