Would this work? Assigning a few diffuse textures, and then have a script attached that tells it to randomly choose between them for diffuse. Just trying to think of a way to give variety to batched meshes of the same geometry.
changing the texture of the material creates a duplicate material. If you need copies of an object with different textures to batch then you need to put all the textures on a texture atlas , create multiple meshes with different uv coordinates, give them all the same sharedMaterial but randomly pick a different mesh.