mb makes keys according to vin right? and just to make it more difficult, i think there are 8 different kinds of keys per individual car on the newer cars with the flip-out style. i believe one of them is a complete key and another is just the key part. understably, the dealer will reply with "this does not compute" as he wouldn't know where to start with your request. you will have to be creative and do a variation of what david describes. btw, the complete key with the electronics cost almost $200. the key part by itself is about $15...
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"