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

NinoTNC A4 Housing - the “official” case

Nino TNC Case - Modified case with a tighter fit (and relocated LEDs) by: Jez - M0JXW

NinoTNC standoff - a simple open standoff frame with split pins
The pins just fell off mine straight away - print settings probably need some work.

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.

More forgiving case by Matt M0MFZ - a case with some clever features to allow for ‘less than perfect’ kit builds