The MRI is done and I'm going to send Penny's cheek swab out to find out what the rest of her breeds are! It also will let me know about her health, which is excellent!
I've thought about the doggy DNA test for my dog. He's either a nearly purebred Corsican Dog (Cursinu), or a total mutt that sorta mashed itself together to look like that. The picture on the Wikipedia page looks like my dog at 3-4 years old.