Depending on the situation, I think it's usually better to seperate the models to different apps instead of using a single app with a models.py-package. This way you'll have seperate views, forms, urls, admin, templates etc.

For common functionality (ie an abstract model or a mixin that is used/inherited by multiple models/views) I like to add another django app named common or core that is used by the other apps.

I'm using Tornado, not Django. I just want to use Django as an inspiration for my app structure.

The problem with Tornado is that it doesn't come with an in-built ORM like Django, which means I need to actually create a connection to the Mongo instance I'm using. Hence the confusion. Python doesn't have initializers like Ruby does (that I know of).