Unless you're into adapting forks from another bike, the only 'bolt on' option is adding a second disc and caliper to the right side of your existing front brake. It takes some trial fitting and machining/shimming to get the caliper arm true, and you'll need to replace the master cylinder as well. My 550F has dual stock discs, calipers, and a sportbike MC of unknown origin. It stops on a dime with excellent feel and modulation from the lever.
I can't speak from experience, but perhaps a later 750 or early Goldwing with dual discs could give up its MC to a 550 application