Funny, I was going the different way.
Build up my NAS with an old PC and Debian linux distribution - worked fine for some time (RAID5 for data with 4 discs, RAID1 for the OS with 2 small discs - FTP Server, File Server, Mediaserver). Then the technology changed to SATA and I ran out of space with my HD's - so I decided to try a commercial NAS with the possibility to put add ons on it - so I decided for the N5200.
The old one is now used as backup device, but now without protection of the HD's.
We seems to have similar needs
I have a SAT receiver with HD and network connection, I stream videos and music via hardware clients from the file server.
Wish You could luck with Your project and may be You keep us informed.
br
Peter