Update: Hotel Alberto Beretta in Varenna is listed as having an elevator but when I contacted them, they indicated it is for luggage only.
It is a small elevator which we just used to get our luggage up and down (when we were there I don't recall that it was strictly limited to luggage, though). It's not a big building, so for us the stairs weren't a problem. I liked the hotel and would stay there again.
Most of our tours in Europe have included at least one hotel which didn't even have a luggage elevator.