I initially planned on having the ability to override the 4 channels using buttons connected at the end of another ethernet cable, but I remembered this video by big clive: 

I quite liked how these looked and the 4 button version would be perfect. I picked up one and a 4 channel 433MHz receiver. 

Prototyped on the breadboard:

The RF receiver will be on a board that can be plugged into the single RJ45 jack that is used for overrides. I broke out the 3 different voltages, gnd, and 4 inputs on the connector to give flexibility for other expansion. 

and on the RF board the receiver is powered by 5v: 

I also broke out the learning button so it can be accessed from outside the case.