I doubt anyone will have the finished bevel gears for the diff off the shelf, you would either have to cut them yourself but they would not be true bevels or maybe get them 3D printed and cast, should be able to run cast on cast if they are done well, final option would be to find a friend with CNC and a 4th axis.
Not sure if MJ can do them and Malcom who used to do them does not do so much now and they don't have the machines for true bevel gears.
Edited By JasonB on 10/04/2019 18:28:16