Here are some of the case models we've been able to locate:

NinoTNC A4 Housing - the “official” case

NinoTNC standoff - a simple open standoff frame with split pins
The pins just fell off mine straight away - useless.

NinoTNC mounting plate - a basic standoff mounting plate for the A2, A3, and A4. Uses M3 hardware. Has two countersunk holes for wood screws etc.