The first member of a range of InDesign export scripts has become available.
Crawler.ID2MD provides InDesign-to-Markdown export, with a best-effort layout approximation.
Crawler.ID2MD is highly configurable. As of today, the software is available for testing and purchase here:
Installing the software gives you a 20-day fully functional demo. After the 20 days are up, the software needs to be activated for further use.
Documentation is still incomplete; the work-in-progress is available here: