Mirrors are possible to create in the Torque Game Engine, if you're willing to create a new interior, transmit this to new clients (they'll have to rejoin the first time you spawn that mirror model) and force them to relight the mission which takes a few seconds every time a mirror is made. They also don't reflect your character in first person. (They do in Age of Time because the character model is always drawn, for Blockland it isn't drawn for you in first person so you can't see the inside of your head or helmet)
Dynamic brick-mounted mirrors in the way you are thinking of are currently impossible.