If the main thing you like about Django is ORM yet are considering a DB layer that doesn't require an ORM (like mongo) - have you looked at Pyramid (previously Pylons)?
Besides giving you only the tools you want, it works very well with a driver like PyMongo. If you're starting out small you can also get free developer hosting with MongoHQ to get you up and running quickly.
Oh and you get to keep doing things in Python which is very nice. I've also had no problems with MongoDB for my web needs and I've worked at a few places that use it without the scary data corruption stories told to developers in order to make them keep drinking their Java.
Besides giving you only the tools you want, it works very well with a driver like PyMongo. If you're starting out small you can also get free developer hosting with MongoHQ to get you up and running quickly.
Oh and you get to keep doing things in Python which is very nice. I've also had no problems with MongoDB for my web needs and I've worked at a few places that use it without the scary data corruption stories told to developers in order to make them keep drinking their Java.