Andy, I find what you say surprising, but plausible. I'll let others who are more knowledgeable than I am comment on your theory of reputation being king. I would have thought that there are knowledgeable potential buyers would be able to judge the quality of restoration for themselves. Also, I think anyone on this newsgroup who has followed your progress would say that what you don't have in name, you well make up for in time, effort and meticulous attention to detail.
If what you say is correct, you could consider trying to get the car sold on consignment by a high-end Mercedes dealer to whom you could give a percentage. Possibly their name would allow you to sell the car for a much higher price, making the commission acceptable.
One of the reasons I mention this is that, when I was looking for my Pagoda, 20 years ago, I initially came across it at a Mercedes dealer. I quite liked it and was considering buying it, but felt they were asking a bit much. So I kept looking. A few weeks later I saw a private ad and, when I went to see the car, it turned out to be the same car, for about 20% lower asking price. I did not let on I had previously seen it, and on talking to the seller, I eventually understood that he had had the car with the dealer on consignment. Of course, I was very happy to have the opportunity to buy the car for a more reasonable price.
I could see the psychology of getting the car sold by a reputable dealer could make an important difference if the pool of buyers is less knowledgeable, and the item in question is a car in pristine condition.
Anyhow, my suggestion is that, when the time comes, you try to sell it; see what you might get; and then decide whether it's worth it.
