I am a great lover of the W126 cars. They are among the last of the big ones built and engineered to a cost no object basis, and with proper care will last you to interstellar mileage.
This one is my 1991 AMG version, that I bought when it was near new, seen this year. The man who owned the Beverly Hills Hotel had owned it but his wife said it was "too flashy for Beverly Hills"
and made him sell it and buy her a new BMW, he told me, when he gave me the records he had on it.
This same one now has 171,400 miles on it and still looks and runs great.
When new, they were the flagship of the entire Mercedes Benz line, the 560SEL sedan and the 560SEC coupe. MSRP on mine, the black one,the last model year of them, (1991) was $84,500.
But they last, they look good, are safe as a house, are actually engineered to cruise at their top speed ALL DAY LONG, are comfortable, luxurious in an austere way, are designed to be VERY easy to work on, parts are ALWAYS available, and are fun to drive, and even the seats were designed by orthopedic back surgeons.
When new, they were the cars of plutocrats, captains of industry, multimillionaires, rock stars, footballers, diplomats, dictators and people that wanted, and could afford, the very best. For that reason, the cost of fuel was of no concern to them, and if you are worried about that, these cars may not be for you.
If you can do it yourself, or have the assistance of a good independent mechanic or shop to help the overall cost per mile to run is not that bad.
As said above, the most expensive Mercedes Benz is very often the cheapest, so look for the best condition one you can find, preferably with ALL books and records and few owners.
That beat down one you saw for $900 on Craigslist, could easily surprise you with $7000 worth of work needed...
A word about the big Ford products, I also am partial to them, the Panthers.
I have owned four, a 1982 and 1988 Crown Victoria, and two of the last ones, a couple of 2009 ones, a Nautica blue one that I racked up some miles on,
then traded in on a gorgeous toreador red one quite recently, and loved both.
They are in some ways, quite alike, ie, long lived, good build quality, comfortable, high mileage long distance cruisers, and very reliable, a LOT like the big old W126 Mercedes. I love owning one of each of them.
I think, if
you have had a good experience with a big Lincoln, they could work out well for you.
I have written a buyers guide back in 1998 (not updated) that is a good introduction to them.
See it here:
http://www.mbcoupes.com/buyersguide/buyersguide.htm
Also,
www.benzworld.com, has a very active and busy subsection in the w126 section, and that forum is by far, the best worldwide forum for these cars, it is a fairly tight knit community and has the best advice.
I am selling my 3rd one, (the 1990 Smoke Silver coupe)
and the following 52 page story, with pictures, is quite entertaining about how I came to do so, judging by the over 20,000 hits it has received so far. But it takes over 2 hours to read, though, people have said.....
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1518603-stealth-reposession-1990-smoke-1990-sec.html
I am selling "the Smoke", the celebrity repo car, to a fellow enthusiast. It ships out to Florida tomorrow, to a new owner I have ensured will take good care of it.
Good luck with your search, some good ones are still out there. Sometimes the best ones are actually sold or traded on enthusiast forums like benzworld.