I've replaced my mirror creation with the commercially available telescoping rods. They have a magnet on the bottom, and a ball ( or on mine an LED ). You stick one on the hitch ball and one one the hitch. You keep them lined up as you reverse. When you get to the hitch, the rod on the hitch ball is knocked off the hitch and you know you are right on. You do still have to check that you have the hitch at the proper height for the ball.
Mine is called Easy-Hitch by Jacko Enterprises
Go here to download a PDF on the unit: http://www.shopdragonsden.com/product.php?id=33
A similar system can be found at etrailer.com for less money ( no LED ).
I'd probably still be using the mirror, except my daughter bought me the rods as a gift. They do take up less space. However, the way you shut off the LED to save battery is by unscrewing the red lenses slightly. So far, I've lost three batteries and they aren't cheap. Haven't bothered to replace the batteries.