I agree that shared data centers and an international team of AI researchers would be best. The key, though, should be absolute transparency. All the data should be accessible to the public in such a way so that the resulting models can be replicated. Even if it's unlikely that anyone would have the hardware necessary to do so.

The only concern is copyrighted works in the training data. Example: If a government filled it with millions of books, that data should be accessible to the public (to verify everything). However, that would piss off publishers to no end.