What were the all time greats of postal delivery fleets? After the horse was superseded by the far superior and usually less smelly automobile of course.
There is the classic Jeep DJ5 and the venerable Grumman LLV, about to be superceded by the mediocre and overpriced Mercedes Metris. But what about before that? This article is a good overview, but I had difficulty finding a comprehensive history in my five minutes of googling.
There have also been many failures; vehicles tested and found wanting. How the Ram Promaster has not become one of those I do not know.
What do you know, Oppo?