I have a team of several people writing, translating, and editing whole books in Markdown format. The biggest issue I've run into so far is that none of the editors I've tried people on support footnotes. As one book we're just finishing has 1,216 footnotes and most of the people touching the file are confused by markdown syntax anyway, not having a preview to confirm that they got it right is a significant pain point.
Are there any GUI editors with Markdown preview panes that support footnotes vis-à-vis Pandoc's / PHP Markdown Extras' syntax? OS X or web based would be nice, but really anything would give me a place to start for at least some subset of the team. I can afford a few bucks per license if there is something out there that eases the pain.