Hello
I am a proud owner of volumio (1.1) on RPi in combination with a hifiberry DAC. I am very pleased with the built and music quality. One thing on my wishlist is to move the OS and related file system to an 8 or 16 gig usb but i did not find any working example and many requests… Is this something that could be on your list as 1) USB sticks are inherent faster and 2) they have a longer life expectancy. Can you create a tutorial how to do this or is the volumio design not supporting this architecture? I do understand the SD card is always necessary as it contains the boot instructions 
Philip Van Cleven
Hello!
(Pardon the late reply to this post.)
I’m still learning about Volumio, so I don’t know yet whether there are any specific issues with moving the OS files around, but I just completed a configuration like this and thought I’d chime in. I recently installed Raspbian “Wheezy” configured to run off a USB stick on a RasPi, and am now using this system to run a small Minecraft server (for science, of course). I can confirm that it works, even under the load presented to such a server.
I’m using the documented procedure found here, which works a treat. The RasPi boots from the SD card, using the “/boot” partition, and runs the OS from the USB stick.
Essentially, as the normal Raspbian distribution has the “/boot” and “/” filesystem mounted on separate partitions this is an easy process. I’m embarrassed to admit I don’t know yet whether Volumio is configured similarly.
Hope this helps.
–joe.