If you want a great value for your money, look into the VW Phaeton with the W12. It has the same Quattro AWD system as the A8, but was essentially the production test bed for the Bentley Continental (GT and Flying Spur); the chassis is shared amongst the three models, but the Phaeton was used as the test basis prior to rolling out production with the Flying B. The Phaeton has suffered large depreciation; you can pick one up for relatively little money, but have a vehicle which shares much of the DNA structure as the Bentleys.
BTW- We are on our 3rd Audi (I bought my wife an '04 A4 1.8TQ Avant 6sd Sport) and I think this will be our last German. Even with our extended CPO warranty, every service visit ends up costing us between $500 and $1k. This last time we had to replace a number of items, including:
-All 4 coil packs
-Fuel pump
-Fuel filter
-Battery
-Coolant flange (again- our 2nd time in 5k miles)
Our prior visit required:
-Timing belt
-Water pump
-New valve cover gasket
What's more, we have to bring the car back again, as our fuel gauge is now problematic.
Wife's next car will likely be a Lexus...