As an interested bystander who is not going to be writing this, I have some questions.
To Logan: how secret is secret? Is “view source” visible too public?
To those who know Discourse’s internals: Could the username be exposed as a CSS class (probably with a known prefix)? My thinking is the [secret] block could be set to invisible by default, and exposed for particular users.
I strongly suspect username can be exposed that way, but that it is not currently.