Structured Tag Naming in Subversion

I've recently started using Subversion for versioning the Leonardo code base. While I've admired the design of Subversion since before 1.0, I'd never really had an opportunity to use it on a project.

One of the things I've done with the Leonardo repository is followed the suggestion of the O'Reilly Subversion book in having three top-level directories:

However, it's just occurred to me that, because tags are just copies with their own directory path, I could add some structure to my tags. Because I normally use tags for either checkpoints, milestones or releases, my top-level directories could be:

Even within things like /releases I could have structure such as

I'm thinking aloud but it seems like a reasonable practice to follow. Anyone done anything similar?