The local Ford and Mercury dealerships around here (Nashville, TN) were still stocking these just a few months ago. I had to buy one for my Marchals and picked up a spare while I was it. They were $18.00 each. You might also try picking up a set of the fog lights on ebay - I've seen a couple of complete sets (minus the brackets) go for around 24.99 complete with the bulbs.
These are one and the same. I believe they call them cats eyes I thought they were obsolete but quite the contarary they are readily available. The spare bulb is out in my garage so if you need the bulb number let me know and I will look it up.
Bob