You aren't going to get an OT shirt unless someone ends up passing one down to you. Was never meant to be bought, more of an item with a lot of sentimental value, to show that you were a practitioner who trained hard, etc, etc. Passed from David and some early gen practitioners to guys they met who deserved it. When you wore an OT shirt you were wearing the same shirt that another Traceur shed blood, sweat, and tears with...
And don't even THINK about making a shirt that looks similar to the OT shirt, or the Aussies will kick your ass via the internet LOL.