Well, you could also use ZBrush for rigging. I think that multi res in Blender can work with up to 10 million polys (or maybe this is a work in progress?), but

Well, you could also use ZBrush for rigging. I think that multi res in Blender can work with up to 10 million polys (or maybe this is a work in progress?), but don't quote me on that. I don't see why you wouldn't just go for vertex colors instead of UVs. Polypainting works fine even at 10 million works in all tools I've worked with (zbrush, substance painter, 3dcoat). If there's some reason you'd want UVs, you could just bake them to UVs afterward.