In the latest HPP magazine, there's a blurb about this company:
http://www.braketechsolutions.com/. They're now offering a disk brake kit for '58-64 big cars, based on the '69-'70 big car factory disk brake setup. The price is $1,350 which is not cheap, but it does include a master cylinder and booster.
The thing I'm wondering about is if they'll sell the rotors separately...if they are in fact the same as the factory '69-'70 rotors it would be a good deal, as I understand those parts have been real hard to find these days.