Well you could use pandoc [1] for creating MS Word or other file-formats. As far as I know MS Word is still the choice to use for novelists, when it comes to giving test to editors and a like.

So pandoc could be used for transforming a text into many different formats (even ebook formats).

Might be an interessting thing to look at for the creator of "git for writers" ;-)

[1]: http://johnmacfarlane.net/pandoc/