Heh, that's why I said 60% with doxygen: you can actually use links, have formatted text, have "see also" sections, graphics, and a lot more. The problem with doxygen is, as you've said, that is a post-processing program, but that could be solved if one modifies the CodeCompletion plugin for C::B so it parses the source-code and comments and put's everything in wxRichTextEdit.
However to get 100% of what he's asking, WikiMedia syntax and features are almost a perfect fit.