Yeah, I have had a couple trucks over the years with a 6 ft bed. But they were COMPACT trucks, something we cannot even buy here anymore. Toyotas and Mazdas (the pre-Ford Mazdas), and I have had a couple Rangers. My dad still has both his Rangers, an '84 and a '99. They are both long (7 ft) beds.
It all is about what suits your needs. For me, my little trucks were great, the B2000 could get 25 MPG if not driven too aggressively, and gave me over 400k miles of service. That size truck with a 2.0L or smaller turbo diesel would be ideal. But by the time such an animal was being built, there were no more diesel compact trucks sold here, and now no compact trucks of any kind. The Nissan is probably the closest, but still larger than the old D21 trucks.
But my 4.9L 5sp F150, with a full 8 ft bed, uses less fuel cruising down the highway than my dad's 4.0L 5sp Ranger with a 7 ft bed. When one advantage a smaller vehicle has over a larger vehicle of the same type is fuel economy, and you take that away, then what's the point? I do not drive my truck daily, so may as well have the big one... and if it uses less fuel to boot...
I think the F150 diesel will be a hit. They'll be pricey, but they will sell them. I too want to see what trims and costs are involved with them. I may even consider going into debt to get one before they get banned.