I think they'll start throwing new parts at the car and hope that solves the problem. Even though a new car would be nice, the manufacturer has the right to try and fix the problem first before giving you a brand new car. Read into your state's lemon laws. I live in Florida, and a lemon law suit can be filed once the car has been in the shop for 30 days or the problem hasn't been eradicated after 4 fixes. It's not as clear cut as that, but you get the general idea.
Ford just finished their second attempt to get rid of the vibration noise. They replaced the wheel bearings again today to no avail. They actually gave me a rental this time. They called the FSE after this second set of new bearings failed to fix the problem, so now they are going to replace an intermediate bearing on the front wheel of the car (maybe both?). The parts have been ordered and they are going to install that on Monday. That will be the 3rd fix.
If the 3rd fix doesn't get rid of the hum, the way I understand it is that they get one more shot to attempt to fix it. If 4th fix doesn't work, I'll be going the lemon route to get rid of the car. I love it, but the vibration is unbearable. There's no way I could ever sell the car in the future, let alone put up with it the rest of the car's life! Now that the power steering acted up once (failed on me last Saturday), I full heartedly believe I won't be the owner of this car much longer. I'm not giving up, just not keeping my hopes up that the problem will be fixed.
Just keep up with that documentation!