Ford is introducing a smaller Class 6 chassis cab truck next year called the F600. It will share many of the components of the larger F650 but be the same dimension as the F550. This 22K lb GVWR vehic...
Ordering is not open until early 2020 with deliveries later in the year. I would not be surprised if multiple cab options are available in different wheelbases like you see in the Class 4 and 5 offerings.
The 10-speed automatic will be available for the F550 and bellow, but I am uncertain if the F600 and larger are currently staying with the 6-speed. There are conflicting stories about those details.