There is a website to find mismatched shoe sizes. A couple of decades ago my mom's cousin got hammertoes and had surgery on one foot because that foot was 1/2 size smaller so she clenched her toes to hold the too-big shoe on her foot. Someone told her about a service like this, but this internet version would make it more efficient. The guy on the video says Nordstrom offers this service, too.
http://www.oddshoefinder.com /
It is odd that women who wear suits to work can't buy them measured to fit, the same way men do!