I replaced a cone recently, because one I had had brinelled on one side, the hub was reasonably okay, so new bearings new grease and a cone I found on a solid axle I had recovered from a dumped bike with basic shimano hubs.
That being the cones are not that hard to find, perhaps the LBS?
As to brinelling, sod it on these hubs the wheel still rotates that is good enough and runs reasonably true, but if I were particular, I might have sacrificed some bearings with grinding paste and ground the brinelling out as I rode.