I have not seen a set of Nickel-cadmium plated rotors for a 126, though they may be available. I put a set on my Corvette last year, and searched around a bit, course there were many sources for the Vette. one of the most knowledgeable was Baer in Phoenix. I doubt they carry MB rotors but might suggest a source.
But the issue gets down to what you can achieve with plated rotors. The plating will protect the 'hat' area around the lug bolts, the inner part where the pads don't rub, but the plating gets quickly worn off the pad area, so evil rust appears there just as quickly. Ni-cad plating is normally used for cosmetic purposes where the open wheels like the Vette allow you to readily see the whole rotor. The 'hat" area stays nice and shiny, but the pad area still rusts, until you drive a bit. In the case of my MB, I have the '92 rims, but still can't see the rotor. It rusts a bit around the bolt area but pretty well stabilizes after a while, and causes no issues rather than kinda ugly (but you can't see it).
Again, you'll still get the big-time rust where the pad touches as soon as you drive a plated rotor for a few days.