You could order that option with a 2004 F-150.  Assuming the other
F-series trucks had it too.

 Most newer trucks ride waaaayy smoother than their predecessors. Partly due to
technology, largely due to customer (yuppie) outcry which forced the Mfgrs to seek new
technology. When trucks became popular about ~20 years ago, the manufacturers  started
to move away from I-Beam suspension, manual steering, etc. Things went a bit too far
the other way though. Now, the softer ride comes at the expense of hauling\towing
capacity. Folks want a truck that rides like a car. That F-250 with the plow package
you are looking at will ride way better empty than an F-250 from, say, 1985 with some
ballast in the bed. They were pretty rough. The F-350 was even stiffer.
 At work I routinely drive a 1989 F-350 4x4, 460 cid. That thing will beat you, and
itself, to death without ~3-400 pounds of sand in the bed. With a loaded 30' enclosed
car trailer it rides pretty nice.
 I really like the newer F series trucks (+1995- 2005?). They are a tough, good
looking truck. You just have to think in terms of 90's-00's trucks compared to a few
years ago when buying one.
 IMHO, pickup trucks weren't made to drive around unloaded.
 There was a time when Ford trucks would eat U-joints in the rear driveshaft if they
were constantly driven unloaded. The driveline was set up to be under load (through
the 1970's). My 74 F-250 Camper Special would toss a rear u-joint in ~5000 miles if I
drove it around unloaded. It was almost a maintenence item like an oil change.