Remember that this is not a traditional commercial diesel engine in our trucks. This engine was in fact designed for use in a car. There are many diesels autos running around the US and near half in Europe. Small diesel engines warm up fast and I find mine getting up to temperature in about 7 miles, my regular round trips. The reason that these engines warm up fast is not only the way that they regulate coolant, but because they are high output engines that make unheard of power for their displacement... compared to industrial and older light duty diesels. I think that this "don't drive short trips in your diesel truck" comes from the old days when diesels were huge blocks of iron and low HP. For example, my old 7.3L Navistar makes 25 HP/Liter. The Ecodiesel 3.0 makes 80 HP/Liter, more than three times the power per liter.
I will agree that longer trips are better for any engine and that will result in better reliability and longevity, but not to the extremes that are often suggested on this site.
Finally, if short trips were an issue, the manufacturer would suggest that in their literature, so as not to incur low mileage warranty work. If I only get 60-70% of the miles that Vern got from his engine, I will be most satisfied.