I doubt the model companies will make a new kit of a truck that isn't produced anymore. The truck manufacturers want their current product to be represented and hint at that when licensing agreements are reached. "Is it new or vintage?"
Product such as the: Kenworth T700 http://www.kenworth.com/2100_vir_t700.asp or Peterbilt 587 http://www.peterbilt.com/aero587.3.aspx .are prime examples. A model company could produce both kits - use the same frame rails, front springs, axles, engine, radiator, glass for each, then separate brand specific rear suspension, fuel tanks, fairings, cab, sleeper, hood, bumper, roof, interior, chrome, etc.
Tim