At a first glance NanoPi Duo looks like a combination of Lichee Pi Zero (form, idea) and Orange Pi Zero (ingredients: H2+ and XR819 Wi-Fi). But once combined with the Mini Shield (RPi form factor -- connector and mounting hole positions), USB hub to provide 4 USB2 ports, Fast Ethernet exposed and a short mSATA slot behind a JMS567 USB-to-SATA bridge) it starts to get interesting.   More information in FriendlyELEC's wiki/Github: http://wiki.friendlyarm.com/wiki/index.php/NanoPi_D