I am working on a way to edit google docs using markdown. Many tools exist to convert google docs to markdown and to import markdown to google docs - but none of them make in place edits. The core logic is to convert the google docs to md. The user then edits the md. Then diff the markdown files, and apply the changes back to the source google docs. This way, features not represented in markdown do not get overwritten.

Lots of effort has gone into testing against real world docs. Its beta quality right now.

https://github.com/think41/extrasuite