I've been heavily involved in picking them up mostly in 1/43" either from visits to the Mercedes Benz Classic Center USA, which carries them, or from ebay Germany for about 10-11 years now.
Pauls Model Art is the same thing as Minichamps, and occasionally the US Mercedes Dealers have a limited selection of current models.
One or two of the "Niederlassung" dealers (Mercedes Benz "super stores") I think in Frankfurt or Hamburg still make them available on
www.ebay.de (Germany) as well as hobby stores over there where collecting them is super serious.
Mine are almost all the older ones. I think by now I must probably have about 100 of them, in their cases. Nothing as new as the W220 or newer, though. So many of those, it is hard to even keep track of them, the C, G, R, ML, etc.
Typically they cost about $29-$45 USD. Plus shipping...
I have, I think, out there in the garage quite a few rather unusual ones, that were sold in Germany only.
Such as the 420SEL, W123 sedan and wagon autobahn "Polizei" models, I recall, and selections from various postwar body styles, such as the fintail, ponton, R107 and W113 SL variants, W116, W123, W124, W126, W210 and W140 ones, it was a nice collection, last fully displayed, pre-divorce in a lighted case in my San Francisco home.
Now they are boxed in the garage, up here, someday to rise resplendent again. I would love to get them out of there and display/post pictures.
A few S class 1/43 sedans are sold at a premium, with a particular model diorama featuring a particular German chancellor with the model of the S klasse he rode around in at the time, such as Helmut Kohl with the W126, Willy Brandt and his. It would be cool to have the whole postwar set.
Maybe someday.