This headless board is based on the XU4. Not much info on it but it holds a 2.5" SATA drive, gigabit ethernet.
https://ameridroid.com/products/odroid-hc1-0003a
https://forum.odroid.com/viewtopic.php?f=29&t=27919
Looks pretty good for people who need a low cost small footprint NAS
Being headless I guess someone will have to create an image that needs to be telnetted or SSHed in for setup.