In other threads I've been describing a method to allow live code snippets to be embedded in reveal.js export, using klipse (https://github.com/viebel/klipse).  I have to say it feels somewhat transformative to me, and I wonder if it would be worth integrating into ox-html.  I'd be happy to hack together a patch but I wanted to ask if anyone else likes the idea.  The great thing about putting it into ox-html instead of building a derived mode is that the other derived mode would potentially inherit the functionality directly.