Dude... I've been planning to create exactly the same thing, but I was thinking of making it an online app. Structured export to Markdown or PDF. Free for < x notes/notebooks, but $$$ for larger users.
Just like you, my main concern is how many people are actually interested in something like this? The main target for such a service would be people who are dissatisfied with Evernote and would like to manage their notes manually, so you'd need to somehow figure out how large of an audience that actually is.
What do you think about teaming up on this, at least for discussion and ideas? As for implementation, I was initially going to write it in Scala, but I'm fine with Python too.
PM me if you're interested and we can chat further on FB or Hangouts.
Assil
