I've heard that the Plasti Dip spray works fairly well for car parts and for temporarily doing color changes over good existing car paint since it's removable. Never used the stuff myself, but I hear its somewhat durable since it's rubberized. Might work well for the top portion of the everdrive.
What would be better than paint is if you can find a thin overlay material that's similar looking to the black portion of original Hucards.
Not sure what Stone Age Gamer used for their deluxe version but it's probably (or should be) really durable since they also painted the bottom side. Possibly enamel paint? Honestly, I think the bare PCB looks better than painted. Something with the holes and the trace lines showing through the paint makes it look cheap.