Adafruit FLORA Sewable RGB Smart Neo Pixel version 2 - Pack of 4

Designed specifically for wearables, these updated Flora NeoPixels have ultra-cool technology: these ultra-bright LEDs have a constant-current driver cooked right into the LED package!

Chainable - so you only need one pin/wire to control as many LEDs as you like
This is the second version of the Flora NeoPixels, which runs at at 'high speed' 800KHz communication. Unfortunately they are not back-compatible with the chip-on-back 'low speed' (400KHz) Flora NeoPixels.
Full 24-bit colour ability with PWM taken care of by the controller chip
5-9VDC power (can run at 3.5V but color will be dimmed), constant current 18.5mA per LED (~55mA max total per pixel)
Each order comes with 4 individually controllable pixels.

In theory, the Flora can drive up to 500 pixels at 30 FPS (it will run out of RAM after that). However, after about 10 pixels (or if the distance between pixels is more than an inch or two) the resistance of the thread can affect the power supply. For large quantities of pixels over 10, you may want to consider using stranded core wire or copper braid to provide a "power bus" for the pixels - the current draw will add up fast!