It has been years since I have used Django - do they still expect everything in the model to go in a single file or can you put each model in it's own file now?
Yeah, or another way of splitting up huge models files is to convert models from a module to a package by making a directory models and adding models/__init__.py, models/foo_models.py, models/bar_models.py then doing
Separating models like this is a hint that you may need another app. It has happened numerous times with me now that my models.py gets large and unwieldy, I spends a hour breaking it all out and then I realise my one big God app needs to be 3 smaller ones.