Is a movie prop the ultimate laptop bag?

That sounds like almost any regular backpack then. They can also be pretty weather proof, don't need to be carried in one hand, aren't open topped showing what's inside easily, and padded. Any simple and cheap backpack would solve this exact problem but better surely, unless your desire is to be different rather than just to move your laptop from one place to another with little ceremony.

I prefer to use a laptop sleeve, and then it doesn't matter if it is padded or not.