Have bought the following 2.4" TFT LCD:
The plan is to connect another arduino to this LCD and place it behind the one-way mirror. When the LCD is off, it becomes invisible; however when the LCD is on - it acts similar to a heads-up display and can be used to display information and convert this to a smart mirror.
The following are some of the uses:
1. Display weather information
2. Display missed call, sms information from a paired bluetooth phone
3. Display an inspirational quote / joke, etc etc
The code currently switches off the LEDs when someone comes near the mirror - so that it can be used as a normal mirror. It can be modified to send text to the LCD arduino (via softwareserial) to display information.
The intent is to switch on the TFT when the LEDs are off so that it shows up through the on-way mirror. Similar to this: http://www.homecrux.com/2013/10/12/9583/smart-mirror-2-0-keeps-entertained-playing-music-movies.html