The current ZWave usb controllers are not supported. Actually its the USB chip that isn't supported under Linux. The leviton controller is a serial interface and could be supported easily but it needs someone who knows how to redirect the ZWave interface to look at the serial port (and deal with the PNP serial detection scripts).
Hmmm... well the ZCU201 seems to be supported but the driver needs to support the update z-wave firmware capabilities. We will hopefully have someone at Pluto looking at this in early Jan and also Dan I think is interested in z-wave too.
So in summary, are there no Z-Wave controllers that are both currently available and fully supported to your knowledge?