Papillon mixes aren't very common -- I'd say it's more likely to be something else. It could be a mix of many different breeds, but if I had to choose two I'd say bichon/chihuahua. Chihuahua not just because of the ears, but also the light pigment. Of the small breeds that look similar, I see mostly chihs with red noses, light pigment around the eyes, and light eyes.