I vote for intermediate with some tutorial information sent out for study before the event.
This is a good reference
http://gae4dummies.appspot.com/quickrefs

Also I noticed this report on a GAE Hackathon:
http://www.openplans.org/projects/topp-engineering/blog/2008/08/05/the-chicago-gae-hack-a-thon-and-app-engine-wikis/
Ian says
"""the day kind of wandered by without any clear “let’s start doing stuff together” moment, and the opportunity was lost"""

Ideally we will have some shared project(s) to work on, and actually make something. I'm working on such a project that I'll be able to introduce soon.

We can also talk about the alternatives at PyAtl on Nov 13, two days before....

The registration for the event is going great and I would like to get a sense of the level at which the participants would like to work at the hack-a-thon.