Well in that case you are going to need some significant hardware to do any of what you said above. Modern top of the line scan-tool with the Euro software. Big money.
Or you could start searching aftermarket remote start systems for a work around. Many times these aftermarket remote car start systems have a work-around. Worth a shot.
What does the dealer want to program you a new key?
I dont really have much experience with programing keys or the systems you have mentioned, however I know the amount you are being quoted is way out of line. Perhaps it's time to visit another dealership?
Mercedes maintains records on all keys for vehicles off the VIN# and what they are suggesting sounds more like your vehicle was in a flood, or lost its original computers somehow. Even if all of the computers you speak of were missing, or wiped out they would still be able to order the key to fit the doors and such and program new modules.
Something does not add up here. Either you are not telling us the whole story, or your about to get ass raped. Hope that helps.
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What is to give light must endure burning -- Viktor Frankl