I would expect a wheel bearing problem to be consistent. Not all the time, but everytime you turn the wheel a certain direction. Usually they will vibrate when you turn the wheel either left, or right, depending on which wheel is at fault. Also, a wheel bearing vibration should be slight, mainly felt through the steering wheel, not drastic like a wheel out of balance.
I've been fighting a vibration problem myself, for several months. I've corrected probably half a dozen things, all of which helped, but I still have a slight problem. I believe that there can be a lot of things that could cause a slight, almost un-noticeable vibration problem by themselves, and under certain conditions, all of these little vibrations come together to shake the beedoolies out of the car.
In trying to correct my vibration problem, I've replaced both driveaxle/cv units, replaced front and rear motor mounts, aligned all four motor mounts, adjusted the exhaust system, installed front rotors, installed struts, tightened a loose water pump, replaced all four tires, replaced one wheel, replaced ball joints....Heck, I've just about got a new car, and I still have a slight problem.
