Paul: We've had the exact Python Web framework you're asking about for about a year -- on-the-fly ORM generation, dynamically-created admin interfaces, stupidly-simple CRUD and much, much more... It's just a matter of convincing our higher-ups to open-source it. We're working on that.
Stay tuned. And if you (or anybody else) have suggestions on how to convince management to open-source a product, please contact me. (holovaty.com/contact)