I have a robot underway that has a bunch of small stepper motors in it. I'd like to connect things in such a way that the steppers can be repeatedly plugged in and unplugged using a user-visible ...

There is no Ethernet connected stepper motor on the market, that can be used with standard cables, switches, connectors, and normal (widely used/known) communication protocols.

Designed to terminate flexible printed circuits (FPCs) and flexible flat cable (FFC), the SFVL series surface-mount connector sports a 0.5-mm pitch and measures 9 mm in height ...