As Cloud ML is "just" hosted TensorFlow, once you train the model it stores a .meta file in GCS for you. You can import this in TensorFlow [1] for serving elsewhere if you so choose. Is that what you're after?
The copy on https://cloud.google.com/ml/ under Portable Models says "In future phases, models trained using Cloud Machine Learning can be downloaded for local execution" so I hadn't looked into it further.
Huh... maybe I'm mistaken. Lemme ask the experts and get back to you.
[Edit: Okay, we've decided that the exported model it produces is what you'd expect. We're going to update the landing page, once we can agree on what it should say.]
The copy on https://cloud.google.com/ml/ under Portable Models says "In future phases, models trained using Cloud Machine Learning can be downloaded for local execution" so I hadn't looked into it further.