Last year I completed a prototype LED fursuit harness and have been getting some great feedback on it since! I'll hopefully be wearing it at the Londonfurs Winter party this coming weekend.

Tech specs:
Approx 100 WS2812b LEDs
Arduino microcontroller
Beat detection via electrec microphone and software FFT algorithm
Concealed buttons to change patterns and beat detection modes
4x AA batteries provide about 4 hours runtime