Small, cheap, and simple driver for 16 RGB LEDs
You should look at BlinkM and Bliptronics. Although they don't provide a driver IC by itself but they do deliver ease of use. They are scalable beyond 16 LEDs. There is a good code-base and online help available for these products.

There is a vast variety of RGB LED drivers but they don't deliver ease-of-use by themselves. You may look at:

LM3435
LTC3212
NCP5623
and the list will go on.