Don't laught , if the sceen is detailled, you'll have 0.001 FPS ...
No this method is not good ,and use real mirrors is a lot better and
a lot more less CPU consuming.

You want real mirrors use Ogre3D, irrlicht ,TV3D or Torque or another ...

i'll hope Conitec will put render to texture for commercial editions ...
caus it's a such basic 3D thing