Ask HN: Plugnplay FTP Server for USB harddrives

Thinking about building a piece of hardware. I wanted to get the HN community opinion or in the alternative see if anyone knows of a similar commercially available device.

As the subject line suggests, this will be a plugnplay FTP server for USB devices (mainly harddrives, jump drives. Think WD MyCloud except with multiple USB ports to connect multiple harddrives or thumbdrives. This way I can access multiple drives, easily save multiple backups incase one goes bad (which is just a matter of time), and these drives would be stand alone from all other devices on a given network.