Innous appears to have the ability to play files that are on a USB drive installed in a networked computer. The trick is to get the music folder on the USB drive configured as a shared folder. For me, it was easy to set that up on a MAC and a pain to get that working reliably on a PC. If you have a desktop computer, you could add an SSD hard drive to it and you could easily set up a shared music folder and you would be set up.
In is inexcusable that Innous sells a high end streamer with USB ports and none of them can be utilized to play music from USB devices.