How has the dealership been? Is it the dealership you bought it from? IF they are good and they are trying hard to solve this I would ask if they could put a different set of tires and wheels on it and let their tech drive it. That way they could confirm or rule out the tires/wheels.
Mounting new tires isn't really an option just for testing. They no longer would be 'new' and there's a lot of time involved balancing them. But a known good set off another 4runner (I assume the Tacoma wheels would fit).
Another test you could do would be to have someone with a camera record each wheel by sticking out the rear door windows as you're driving. See if something unusual is happening. A bad rotor or spindle wouldn't be picked up by balancing the tires.
Mounting new tires isn't really an option just for testing. They no longer would be 'new' and there's a lot of time involved balancing them. But a known good set off another 4runner (I assume the Tacoma wheels would fit).
Another test you could do would be to have someone with a camera record each wheel by sticking out the rear door windows as you're driving. See if something unusual is happening. A bad rotor or spindle wouldn't be picked up by balancing the tires.
Sponsored