So far I am not coming up with anything that looks like a real winner. The offline use of the screen-reader is their analog to our dumping things to the printer. I'm not sure that yet more separate files would deliver a net usability benefit in the end. One of the great things about the WWW is the way it often eliminates the middle-man. If we can get to the authors of the Web content, we have a first-party description situation.
Guidelines requiring objectivity are natural for third-party transcription.
I think they are problematical for first-party annotation.