We don't have enough miles on our LR3 yet, but I can tell you that I never bothered to rotate the tires on all the Audis I have owned and they wear evenly. I think full time 4WD or all wheel drive wears the tires pretty evenly.
So do the rear tires on your vehicles turn like the front???
I cannot begin to imagine that front tires would not wear faster than the rear on any vehicle, 4WD, AWD, RWD, or FWD. Physics my friend, physics... You cannot overcome physics.... Oh yeah, then there is materials....
Did you also buy tires from the dealer???
All tires must be rotated and most tire manufactures reccomend 5,000 mile intervals... Your vibration may have come form a buildup of material (brake dust, road grim, etc.) on the inside of the wheel. It may have been deposited on there in such a manner that corresponded to the wheel location (driver fornt and rear, passenger front and rear). When the wheels got rotated, its baseline was disrupted and thus the vibration...
Are your wheel interior walls free of material? Try removing the wheels and scrubbing the interior with a firm carpet brush and soap... Rinse and repeat until the metal is all that is showing...