This is excellent work!  As far as I can tell, we've moved from the prospect of doing more work to the prospect of doing less work.  If we put examples of this new approach in the SRFI template, then authors who wish to can, with little effort, encode metadata in their documents.  Editors and volunteers can then use your tool to extract signatures into a standard format like Ciprian's.  But if the author doesn't encode metadata, we can create the same external file manually.

It would be great to include HTML IDs in the template, too.  That would make it possible for other tools to link directly to the reference material in the SRFI document.  Of course, the IDs would need be extracted by your tool, too.

This seems like a great way to bootstrap the whole process.