You could use key input to rotate through the team colors similar to what it does for throttle settings or insignia switching without adding new interface parts - but a new box to input RGB values sounds lot more useful 
Wait. You can control insignia and throttle in the lab? Since when, how and where is it documented? Is there any complete list of what you can do in the lab?
I looked at what code is in there that could be used as an example. I don't know of any lab documentation so I guess it doesn't exist??
So we do have (not sure if all of them are working properly):
/ (key_divide): rotates through insignias
L: switch damage lightning effects (arcs) on/off
0-9: FXAA preset 0-9
B: increase bloom
N: reduce bloom
+5%/-5% throttle button: increase/reduce throttle
afterburner button: switch afterburner thruster on/off
E: Since when are these functions in there? Probably many years... I won't go checking when this part of lab.cpp has been changed
