In the manual here you can see an overall photo of how each component is attached. The power supply is off to the left on it's own, then you have the main control module, and then the IO points.
Below are the mechanical drawings (as .dxf or .dwg) of the individual 12mm modules. The front end module has the same outer dimensions as the BX9000.
The exact width of the product depends on the rail it's mounted on and the number of IO that you are using.
Power supply dimensions are 2.5" W x 3.5" H x 4" D.