That is just a matter of time; I believe that within 2 years you will be able to buy diesels in many AWD cars or wagons.
The Acura MDX my neighbor has is extremely sophisticsted and a road manchine and has AWD. Honda and Toyota will probably offer Hybrids in all there vehicles first along with diesels in some of their cars.
Agree that on paper the Passat is a near perfect car; good seats realtively quiet, but quite fragile and costly to maintain.
BMW has an AWD vehicle now which will be offered in diesel soon since it’s already available le that way overseas. It’s more of a perfoemanc vehicle than an all-weather carrier.
All cars sold in the US have to meet increasingly stiffer fuel mileage (CAFE) standards, so milege improvement are a must. At all cost, avoid a Jeep with a diesel; it lacks many of the amenities you look for, and the diesels so far have been Mecedes hand-me-downs.