Phil, you probably know this one already but, if you find a plastic tube of suitable diameter (could be toothpaste top,pen top etc), cut it to length and fill it with a hot glue gun. while the glue is still soft put a piece of cooking foil on it and press it in the glue with a marble or similar to give a recessed reflector. when its perfectly dry you can drill it and put in either LED or grain of wheat bulb.
Its very effective and costs pennies
Mikey