Hello Rich and others - I have a bulb for you. I have recently gone through the search process (including a couple of "almosts" that did not work), but I found a bulb that works great in the original fixture. It is the Bulbrite XP Dichroic Halogen Lamp 12 V 50 watt D.C. Bay. I understand that the "Bay" means bayonet base. The model number on the box is MR-16. You can order it on
www.bulbrite.com. The item number is 644350. The bulb does not have the solid glass cover as the old one did, but the bulb came with an optional loose glass cover. It fits, and works well. I did find that my socket was corroded and needed replaced also. Hope this helps.