Cones for old hubs, especially Suntour can be hard to come by. Definitely check out Wheels Manufacturing, as they list the dimensions on all their cones - you might get lucky. Otherwise, if you can determine the actual hub model, you can almost certainly find replacement hubs on eBay pretty cheaply with some patience. (We might be able to help with some better photos of the hubs.)

Lastly, make sure you have them adjusted properly. That sort of cratering is almost always caused by getting the adjustment too tight. The excessive surface pressure causes fatigue on the cone surface, resulting in small divots cracking out.