After putting together the NeoPixel LED Coat, I wanted to test the limits of conductive thread. I found a wool capelet from an online consignment shop and plotted out how to edge the bottom of the capelet with a whole sheet (20) NeoPixels.
My design incorporated an Adafruit Flora, a color sensor, and a button press to trigger modes and the color sensing.
Since each LED was about each about 5" apart, had to reinforce my circuit to combat the drop in voltage across the conductive thread. In addition to doubling up thread on the ground and power lines, I used tiny metal snaps to connect the two lapels at the opening of the capelet to balance out the voltage across the circuit.
Check out my first visit to the Adafruit Show-And-Tell hangout where I shared this project (@3:45):