I have heard a few people talking about this so I thought I would post some information on it. I will be upgrading my front drums to discs by the end of the year, I wouldn't mind joining forces with anyone else interested in doing it on their ride. I know Scarebird has some info on this as well as an assembled list of off the shelf parts. I have found a couple of useful sites that show the process with good pictures and instructions. These sites are for the Econoline (5 Lug) but the layout is pretty similar, if not identical, to the Mustang, Comet, Falcon, and Ranchero:

http://www.dddiscbrakes.com/installation.html

http://www.carnut.com/tech/econo/econo1.html