here is a new blog post (2 parts) with hands-on tutorial that describes how to create apps with both WAMP and Web parts - and using WAMP from Web parts.
Going asynchronous: from Flask to Twisted Klein
Mixing Web and WAMP code with Twisted Klein
Feedback and spreading welcome!
@Michel: would you mind submitting the first part (title "Going asynchronous: from Flask to Twisted Klein") to Reddit? I'm afraid to get grilled for self-posting - my Reddit karma is looow.