TL;DR posted up the earlier-promised example Literate CoffeeScript blog engine: https://github.com/jashkenas/journo
If you want to be an open-source hero -- go ahead and do it yourself ;) It's mainly a matter of taking the Markdown package, and the CoffeeScript package, and pasting the latter into the former, right where the syntax rule for "code block" goes.
I decided to take journo for a spin and wrote this up in hopes you'd continue to work on it.