Hidden bookcase doors are becoming more popular and are available from a number of mainstream sources. This bookcase door from Invisidoor can be found on Wayfair. Made to fit either 32″ or 36″ wide door frames, these bookcases are available in your choice of cherry, red oak or maple finishes.
Beyond the basic door, all of the made-to-fit trim components, thresholds, jams and cabinet doors are easily available from the same site. This makes your install relatively easy compared to custom hidden bookcase doors of the past.