I thought about adding an edit in there to clarify you could do that, but I think the points remain that in the end, you still end up with www. in the URL bar.
Django-nonrel is in somewhat rough shape and your code ends up coupled to the platform anyway. No plausible path off of App Engine except a rewrite. So better keep it small.
I believe AppScale is a plausible way out. I tried to use Typhoonae, but couldn't make it work.
I've been playing with the idea of building a App Engine gear able to run Python apps on top of OpenShift, but my day job is interfering with my hobbies...
For example, my site (justbeamit.com), runs on GAE, but the naked domain simply redirects to the www.