Auto-save forum replies?

Are there any options to allow or support auto-saving or drafts on forum replies/threads?

This question came up from one of our very prominent and active contributors who writes very in-depth replies to a lot of questions in our community. If he is in the middle of a reply and has to pause for some reason (meeting, additional research, etc), he runs the risk of losing what is already written if the reply is not saved/posted. 

We have drafts for blogs, and the ability to unpublish wiki articles, but is there anything similar for forums (other than a browser plugin that saves your webforms)?

Thank you!