The numbers strategy seems like the only realistic approach, underneath the surface, this really is just a question on how to generate a Base N numbering system in a new 'language' where that language is heavily influenced by the particulars of any given problem domain. I worked for an organization that used a similar strategy for issuing e-mail addresses to new employees. People would refer to each other by their e-mail 'codes' rather than names. It got very strange after a while how easily they were interchangeable.