On July 11, 2017, Trainworx announced two new n-scale body styles: W900 and K100 Seminole Tractor Cabs. Pre-orders are due August 31, 2017 and delivery date is 1st quarter 2018.
The W900 Seminoles tractor cabs ($39.95) come in six different paint schemes. Each paint scheme comes with a 36" sleeper configuration. The second configuration for each paint scheme is a either VIT or Aerodyne sleeper.
The K100 Seminoles tractor cabs ($39.95) come in seven different paint schemes.
Six paint schemes come in either VIT or Aerodyne sleeper. The seventh paint scheme, "Truck down the street," version comes in one configuration.
Here is a link to the InterMountain website, which lists these items.
To learn a bit about the history of truck sleepers, here is a link to an NTB blog: The Evolution of Truck Sleepers.
The TroveStar N-Scale Model Train database features previous Trainworx tractor cabs.