I don't have any spare ones for RE Indian bikes but I've looked on E-pay under Motors, subgroup parts and accessories then jus type in harley headlight, bates headlight, indian headlight, or what ever you can think of. I've seen the larger bates type headlights on there for 20 or 30 bucks and the chrome still looked pretty good.
If your old twin still has a drive on the back wheel that works, you might be able to use one of the replica speedometers available for Royal Enfield Bullets or even rig one for a custom aftermarket speedo. Some of the E-pay stuff for REs from India might work for a Smiths drive set up off the original back wheel location. If you could find one of the old RE Chief dash panels you could rig one of the aftermarket Stewart Warner tombstone Speedos to work. Near all the older speedos use a cable type drive. The dificult part might just be getting a cable outer casing to fit up with the proper size nuts to fit drive & speedo ends with the proper length to get it up to the top end. The inner core would be pretty easy to get. They make universal cable repair kits for stuff like that.