[misnome]

I think this partially matches the parts of the criticism about writing a book, and how the notebook is unsuitable - mainly thinking along similar lines to writing software tutorials pages that are fully testable.

After seeing that post I had a look around for something a little like this and found Pweave http://mpastell.com/pweave/ which seems to approach the problem from the inverse direction direction, but I think I'd rather have something like this where the code is marked up and runnable as normal code but transformable into formatted documentation.

This seems like a reasonable match, but it looks like it's explicitly tied to notebooks and I'm not completely sold on the overloading of plain comments for markup purposes. Still, probably a good step.