I've used web2py on GAE and it's working nicely, with most of the GAE quirks taken into account out of the box. Everything has been taken care of as far as making your app work with GAE is concerned. The site I'm running with web2py + GAE is:
The web2py author also admitted a few months back in the mailing list that google was paying him to test out the framework against GAE. So I think that means the GAE support would be production-ready at the very least.