Bravo Company, one of the premier manufacturers of AR15 components and rifles, is now carrying Arisaka KeyMod accessories. From a personal standpoint this is especially exciting, as I'm a huge fan of Bravo Company, and have been shooting their rifles for over 5 years.
The original designer of the KeyMod interface, Eric Kincel, also works for BCM, so the company is heavily invested in KeyMod components like their ultra light KMR handguard system.
The Arisaka Inline Scout Mount was originally designed with the KMR handguard in mind, in order to provide a mounting option for Surefire Scout lights on the top 45 degree angle KeyMod flats.
Arisaka's products can be found on Bravo Company's KeyMod accessories page at http://www.bravocompanyusa.com/KeyMod-Accessories-s/173.htm.