tough to guess on sounds written in emails but we've all been there.
Sounds rotational in nature if it's variable based on speed.
You guessed the obvious ones:
I would think one of the two.
Does the car pull to one side? And after driving does that hub or rim feel hotter than the other side. That would indicate bearing or brake components.
Let us know what you find, and any other diagnostic tid bits you come accross..