So, I tracked down two replacement cones that look like they might work. The new problem, though, is that the non-drive side cone is 2mm longer than the old one. So either I need to track down a spacer that is 2mm shorter than the one I currently have, or sacrifice 1mm of contact from each side of the axle on the rear dropouts. I currently have 5mm of contact with the old setup. Will it be safe to have only 4mm of dropout contact on each side of the rear axle? I'm anxious to get my bike back on the road, however I don't want to compromise safety.