Hi Shake&Bake,
Sharing USB content is possible off the MX. If going with the DroidTV (Android), there are some Samba apps available that allow you to share the USB mount. On the MX IPTV Box (Same hardware as the DroidTV MX but running a custom Linux XBMC firmware), it will automount and samba share the detected USB media.
In my setup I have 1 x MX IPTV Box with a 3TB drive connected, and share all the content to our two laptops and desktop computers. I do have a dedicated Ubuntu server, but prefer to go green, so power it off and have all the popular kids movies, TV-Shows, etc. on the 3TB drive.
The MX only consumes about R80 worth of electricity a year so I leave it running 24/7