Good for you :) please post it when it's done. I got a chuckle out of the python/Tex thing - I was chatting with a friend recently about how we both want to start writing, but none of the writing apps feel right, if only there was a markdown-simple native mac app that would spit out latex, etc etc. We ended up agreeing we'd probably spend more time on the app than actually writing - kudos on doing both.