I'm kind of amazed at the SLOC, ~600 lines for the whole thing. Flask is much bigger and depends on Werkzeug (~20K?), heck even Bottle doesn't come in under 1,000 lines. That is incredibly attractive.
Yup I plan to keep it that way too. I believe there is enough flexibility in Martini to cultivate some great functionality around the martini-contrib repo. There is already some pretty awesome things landing there https://github.com/codegangsta/martini-contrib