Sherwin Williams sells piano black lacquer in gallons . You will probably want to use a primer or sanding sealer compatible with lacquer before proceeding to the lacquer. The surface needs to be absolutely smooth prior to applying the lacquer or the imperfections will show in your finish coats. You will need a spray gun, 8+ coats of lacquer, and will have to rub the finish out multiple times (wait at least a week after the final coat before rubbing out) to achieve the sort of effect you see on pianos and high end speakers. Many finishers use 3M and Meguiar's auto polishing compounds for the rubbing process. I don't know if it is worth it to you or not, but the above is a lot of work.

Stu