I've never sat in a truck seat that was ultra comfortable. That said, if such a seat existed, it would have to have a seat heater. Seat heaters are great for sore back muscles!

The closest I've seen to a really comfortable truck seat was in a Buick SUV. It was the Buick version of the Chevy Trail blazer. It was around a 2005 model year vehicle. These seats were reasonably soft and adjustable. It seems like most newer vehicles have hard seats.