MotherBone PiOne is a new type of super I/O 'cape' in the form of an industrial 3.5" motherboard for BeagleBone Black. It can also use Raspberry Pi Simultaneously!
Check it out on kickstarter right now!
https://www.kickstarter.com/projects/532391021/motherbonetmpionetm
Or at the manufacturer www.aplusmobile.com