I don't know about the "E" class but fobs are NO longer available for us 140 owners, period! I was lucky in that I got one for my '97 CL600 a couple of years ago from the local dealer. I showed my pink slip, it came from Texas, the parts guy walked out, verified the VIN and clicked the fob a couple of times, and that was that. Total price was a little less than $200.
I would suggest dieselguy that you contact the Classic Car Center in Irvine, CA. Ask for Thomas Hanson in the Parts Dept. and see what they can do for you. They don't do any car NEWER than 1997 but the they have been my rock for a new bumper and a new wiring harness. I have also had great luck with Mercedes of Scottsdale. They don't charge Kaliforniastan sales tax but they do charge for shipping. I just got new radiator hoses from Germany from them at a price FAR LESS than the local dealer. And they came right out of the factory, not China.
Anziani
'97 CL600 69K