Ring Central Achiever should work with Box.com too why limit itself to just the few listed add a few more so everyone can benefit from this great feature that stores all call recordings. Can this be done?
RingCentral archiver lets you archive to your own SFTP server. Box.com can connect to an SFTP server. Maybe for lack of a current integration you can make something work to push your archived data through an SFTP server and over to box.com?