Tazz

The problem is the way the H1 bulb standard or HID on most other vehicles is secured inplace. The H1 on almost every other vehicle is held inplace by clips that secure the lamp from the back of the housing. Ford decided to forgo this method and make a adpater that twists into the foglight housing instead of secured from the back. So if you get a HID kit with the H1 bulb you have no way of securing the base of that bulb to the housing since you can't just swist it in without using silicone, JB weld or the like to attach and secure the HID lamp to the housing.
If I still have the pics of exactly what Im talking about I'll load them up to show you why it's impossible without modifiction to the housing or bulb using the stock fog light.
One more option but it requires a dremmel and time is to get a 9145 HID bulb/base and file down the 3prongs about 1/2 mm and bevel the edges of the prongs so that it will twist correctly and fit properly. You gotta be precise or the gasket will not seat in the housing correctly.
Tazz