I finished and tested a new version of the BreatheDot that is the same form factor but now features a programmable APA102 2020 RGB LED. You can use Adafruit's Dotstar Library to program it.

I always wanted to do it because I really like RGB lights and I find the effect of fading from color to color to be quite mesmerizing. The photo is in the gallery, and the design files have been uploaded as v3.1. It uses a single CR2032 battery to run the LED and the ATTiny85. The Data Pin is PB1 and the Clock Pin is PB2.