Forensic scientists are already trained in footwear impressions. My undergrad was in forensics, and I did most of the things discussed here. Doesn't philly have a forensics option?
I think Forensic Podiatry is relatively new, as a matter of fact, i did not find out about til last year some time. The more i read about it; the more drawn in i became. There are some interesting articles on line (search: forensic podiatry). It is, without a doubt, a very cool option, but you would probably have to really throw yourself into the profession.