Investigations are proceeding as is my test-driving of Discovery 4's with the intent being that if I have to buy one it will have a sticker on the rear window... 'My 200 had a vibration that Toyota couldn't fix. I did it myself with this....'

If a vibration is driving you crazy, I'd hate think what all the little problems you"ll have with the LR would do to you!It's interesting that we haven't had more people complain of a vibration here assuming it's a widespread issue. I have a very, very slight resonance in the steering wheel when ever I'm driving up a slight incline (the vehicle is under a bit of load) and the RPMs are at around 2000. Again, it's very slight but enough for my wife to ask, about it - and that says a lot!
Next time I'm in for service I'm going to ask about it and see if they have any bulletins.