a little opaque projector you can project+magnify+trace any images onto the walls..
then "paint by numbers" so the walls themselves are totally pinball. after that adding some decorative stuff to the full mural background, as an idea anyway..

aww bummer, thought this was for a large dedicated game room. I used little opaque projectors a lot when I was doing stained glass work, great toy for making cartoons.

those look VERY cool John, are they cut-outs from actual sideboards? same could be done mounting a decal to sanded painted ply, might be a nice for sale item and look great on a wall maybe mounted with standoff spacers. (3/8 ply saving shipping weight?)