Capacitive switches are sensors ; some use oscillators which cease to oscillate when the touch capacity exceeds some limit. For your application I would rather recommend a tactile sensor, a contact pushed through a foil like in cell phone control panel.
I guess easiest way to do it is to use Microchip microcontroller with integrated capacitive sensing module for example 16f707 i used.
It is actually very easy to make this
here are example codes and explanations at links on these pages
You can use a touch sensor circuit,
**broken link removed**
The circuit uses very low voltage which is safe for use in the bath room.
The capacitive sensor use QT100 IC and works under various material.
This means that it is possible to waterproof the touch sensor for bathroom use
The sensor can be interface directly to "PIC-117 AC relay switch" to switch on the 110-230Vac radio, www.pic-control.com/product/PIC-117.pdf
The relay is a non mechanical switch (Triac), which can be switched on using very low dc voltage. The switch will switch on at the zero crossing, and does not create much noise on the power supply line. Compare to a mechanical switch, it is much more smaller, and less maintenance.