I'm not sure if this fits all your needs but there seems to be at least some meaningful overlap: http://developmentseed.org/blog/2012/june/25/prose-a-content-e

I'm not sure if this fits all your needs but there seems to be at least some meaningful overlap: http://developmentseed.org/blog/2012/june/25/prose-a-content-editor-for-github/ http://developmentseed.org/blog/2012/june/25/prose-a-content...