black pedal with the electronic sign/symbol for GAIN (if there is one) or an op amp sign or something, with the symbol itself split down the middle into two colours,red and green (keep the symbol small and subtle)
the single LED changes into red or green (to correspond with the gain symbol) depending what toggle/gain structure/mode you are on
at the bottom of the pedal, the famous BARBER sig with "gain changer" in the same style writing."gain changer" could again be the red and green
i'm too late,i know, but it would look cool,whaddya think?