Thank you. I also appreciate you putting your app.yaml on the code repository - it helped me get started today (before seeing what you had done, my own had not been customized for wsgi, just Python 2.7).
I'm definitely interested in learning the relationship between the DAL, 2.7, and transactions. I would like to help improve GAE support in the DAL, so if there is anything I can learn from your experiences, maybe we can use it to improve web2py code. I believe this is the killer feature of web2py - being able to deploy to GAE easily while still being quick to start, and portable. Any interest?