To be honest, i see no future for owncloud anymore. The core developers as well the founder owncloud, left owncloud and started Nextcloud. I am rather suprised that you missed this. Were you living under a rock XD.
Nextcloud is going to be the way i think.
I am also planning to buy a mSATA, but those guys are seriously expensive :(. I plan to buy the Samsung 840 evo 1 TB.
If you’re at it, maybe an idea to also run some torrent “server” on it also. I mean Omnia is day and night on, so why not use it for the better if you also have a mSATA SSD in it right?
Transmission is a good torrent applications(webbased possibility), although i am planning my self to use Deluge(also webbased possibility) within a Ubuntu Linux container, because the package has some issues with openwrt.
On your desktop you can have a plugin that sends the torrents directly to the torrent client on your omnia and off course do the necessary setup that it sends you an email when it is done downloading the torrent. Or/also you can maybe use Sabnzbd(webbased) for Newsgroups.
BTW, i am not sure which version of the Omnia you got. Altough i think 1 GB is more then enough, but i myself ordered the 2 GB version.