When it comes to heavy SUV diesels - Mercedes GL is probably the only choice on American market.
Audi and BMW in last years sell SUV diesels here as well, but smaller and after VW fiasco -selling diesels in USA become tricky procedure.
I treat my family to Mercedes and mostly diesels for last 20 year and thanks to Internet, I know more about them than California Mercedes dealers ;)
Probably
The best Mercedes diesel forum is here. Years ago I used ML320 for pulling 4000lb TT and with short rear it was one of the best TV available. Never needed WD bars, while relatively small engine allowed me to beat California traffic. One time a friend following us in Honda sedan, had hard time to keep up on 200 miles trip.
Right now we own E320 Bluetec and love the car.
It is 6 seconds "bad-ass" performer, still delivering 35 mpg.
The early 350 Bluetec had 210 HP, at about 2012 they tuned up 240HP.
Are you planning to buy new (rumors are MBUSA seized diesels import after VW incident) or used one?
You will find me on MB forums under slightly different handle, but you will tell it is me
Beware that modern diesel engines require top-end specific oils, when not too many of them are available in USA.
You can find some reports about 350 Bluetecs seizing at low mileage, when USA dealers did use cheaper oils.