Wheel bearing is a good guess. I had the same symptoms and spent some time messing with the brakes (the sound was just like worn brake pads) before I fixed it by replacing the hub/bearing. I also did not detect any play in the wheel, I just replace the hub because (a) the symptoms fit and (b) I couldn't find anything else.

If you replace the hub/bearing yourself you need a female torx socket, I forget the size. Just pointing that out because you might not have one in the toolbox (I didn't). Also, I mail ordered a replacement hub and it did not come with the required new bolts although they were in the web site's picture of the hub.

Terry