Back in the day Toyota, Ford/Mazda Datsun, Nissan, Dodge, Chevy and a few others had 4 cylinders, some diesel. Of course these trucks were a tight fit for the driver if you were over 5'5 in height too.
Now with the bigger trucks the smaller engine wont cut it if its being used for work vs a passenger vehicle.
Having said that, there nothing like ripping around with a 7 liter 8 cylinder engine.