KBP V60 and V80 are the only two off the shelf option I am aware of. If you don't mind soldering, TMK Alps64, Infinity 60 and Clueboard PCBs all support Alps/Matias. Infinity 60 also has a bonus feature: because of the tight tolerance, you don't even need soldering. You can just plug in an Alps switch and it will work, making it basically hot swappable.