The short answer to your question is no. There are however highly polished bricks available in chrome and gold that reflect more light then others. These bricks tend to be rare and expensive.
There is a non-purist solution that works well using metalic paper or tin foil which can be found in craft stores and supermarkets respectively. The material is relatively cheap, flexible, can be as small or large as you like and provides a decent reflective surface. You can use double sided tape to stick the material onto slopes or you can hold them in place using bricks.
The Detective’s Office & Barber Shop (10246) includes the first mirror in a LEGO set. Until it is released on the 1st January 2015, it is very difficult to say if this part includes any rear studs that can be used to attach it to other bricks.