No pic at the moment, but I can say that the front looks exactly like the rear but with the corners pinched inward.
Currently I don't know of another replacement pad producer for these pads. Given that, if it was me I would find a piece of round stock the diameter of the Kool Stop pad insert section and reform the holder around it - close it up a tad. Grab a couple pairs of pads and be good for a lifetime. I also wouldn't hesitate to make the John Bull holders fit if I was confident it would work without mangling things. Who else is making replacement pads for them?