Please direct all thanks for this over to http://github.com/jwalton. He's been toiling away on these for a couple of months now, originally as a bit of a skunkworks. Managing to get them merged in cleanly to an oft-changing code generation codebase was no small feat.
Edit: If you're having any trouble getting these to work, `npm cache clean` and reinstall. I screwed up the initial publish.
Important Update: Just pushed out a 1.6.1 release which patches some bugs that snuck in this morning. Give it a spin.
It also makes it possible to generate source maps in the browser itself -- so if you're doing anything fancy with eval-ing CoffeeScript on the client side, you're in luck...
... now, time to hit the road.