In reply to mark k..

Here's a quick-and-dirty script... note that a) it'll need adapting to fit situation of the site b) it relies upon having already audited that there are no unexpected users outside of the 'customer' role, and that you don't have hacked code that might give false results (or have copied your user tables to a clean WP install). c) I don't have the resources to give any help with customising it.

This forum doesn't like direct code posts; so, you'll need to download it from here: http://david.dw-perspective.org.uk/tmp/audit-users.txt