I don't think we should rule out multilinguality right from the beginning, *especially* not with a categorization module. I18N is a conscious decision that affects scalability anyway!
The fact that the current solution is not I18Nized doesn't mean that a future and hopefully *better* solution doesn't need to support multiple languages.
I don't know anything about I18N yet, but a viable solution could be to add the default name to acs_objects and localized names to acs_object_names.
Maybe Peter or Lars could tell us a fair bit of how I18N could work here and how it would affect the categorization package.