I used GAE and Django to build a Facebook application. I used http://code.google.com/p/app-engine-patch as my starting point as it has Django 1.1 support. I didn't try to use any of the manage.py commands because I assumed they wouldn't work, but I didn't even look into it. The application had three models and also used pyfacebook, but that was the extent of the complexity. I'm in the process of building a much more complicated application which I'm starting to blog about on http://brianyamabe.com.
