gang spacing of locking devices

Is there anything that supports the gang spacing of locking devices. For example if you want to install (2) L5-20 receptacles you'd typically use 3 device boxes and the center to center between the two would be 3-5/8". They make that matching plate and everything. Are you permitted to mount them side by side @ 1-13/16" center to center between? I can't find matching cover plates. I have an application that wants 4 ganged together using only 4 device boxes.

Smart $

Esteemed Member
ANSI/NEMA WD 6 provides the dimensional requirements of plug and receptacle wiring devices.

The screw hole spacing for multigang wallplates is 1.812" ± 0.010"

The maximum connector body diameter is 1.860".

The standard does not specifically prohibit a manufacturer from making a combination of devices that would fit together and function as desired. However, I quite doubt any exist to be acquired through the general marketplace.