I know the head shape (minus the wrinkles) match up but other dogs also have the similar head shape and since it is a mixed breed 2 or more types of dogs can create that same head shape.

Oh, and I didn't necessarily mean people on this site always say shar-pei. I had been looking at pet-finder recently and it seemed like any medium-large size dog with wrinkles was listed as part shar-pei. I just have a hard time believing that there are that many stray shar-pei's running around out there, considering I work at a dog training club and have yet to see someone come in owing a shar-pei - I guess I see them as a slighlty more rare breed so I'm less likely to believe that a mixed dog is part shar-pei.