I've done it. I used a dual master from a 60's full size Chev car (The first year of dual master cylinders. Can't remember the exact year ('66 or '67)) It's fairly straight forward. Your brakes run on two circuits instead of one so if a leak happens in one line, the other line will still work. Safer because you still will have some braking power. Many vendors sell the bracket. Check out Cletis' tech tip here: http://www.stovebolt.com/techtips/master_cylinder/index.html

It's a small world, but I wouldn't want to paint it.