If you want a NAS device with the latest version of Windows Storage Server, you're in luck: Thecus has announced that it will begin updating its rackmount devices to WSS 2016 throughout the year.
W2810pro RSS
If you're looking for a small server rather than a custom NAS device, you might like the Thecus W2810PRO that runs Windows Storage Server 2012 R2 Essentials, giving great power with a learning curve.
