So an iPad or old phone is the preferred way to control a remote Volumio node, but there must be some thin, perhaps active HDMI cable containing USB to a tiny touchscreen for running in kiosk mode. Plus power is required for the display too.
What are you using as a cable and display for Volumio in Kiosk mode?
Hmm, perhaps three wires, HDMI, USB and Power to any display will suck and in all cases one should use a WiFi web browser. So can we expand the scope to include web tablets or perhaps open source phones: