Make your own smart LEDs with the same chip that is used in our NeoPixel strip and pixels. This tiny SOIC-8 is fairly easy to solder and can drive a single common-anode RGB LED or three single-color LEDs of your choice. (The outputs are NPN transistors so they won't work with common-cathode!) The outputs are each ~18mA constant current so the color will be very consistent even if the voltage varies, and no choke resistors are required making your design minimal.
The pixels are 'chainable' by connecting the output of one chip into the input of another - see the datasheet for diagrams and pinouts. To keep the chip small, there is a single data line with a very timing-specific protocol. Since the protocol is very sensitive to timing, it requires a real-time microconroller such as an AVR, Arduino, PIC, mbed, etc. It cannot be used with a Linux-based microcomputer or interpreted microcontroller such as the netduino or Basic Stamp. 7:53)