I'm horrible that I just realized these things recently. Bonsai's tail is constantly curled up and rests on his back. When he wags it, it just stays like that. He also has completely bald ears and legs, and the top of his head is balding as well.
My best guess is, along with Pomeranian, he also has some Chihuahua in him. Any other guesses? Please excuse the quality of the picture. This is why I don't take pictures very often. I need to buy an actual camera some day.