Sure, it's here: https://github.com/marcmerlin/Neopixel-IR (but go to the end of this page for more details).
So, I have 3 versions of the shirt, let's go through them depending on how complex you'd like to go:
Multi Color LED strip, non controllable
It used a 12V controllable dimmer: https://www.amazon.com/gp/product/B00MHKCTLE which can simply change the brightness of the LEDs, which are of a set color. I bought the LED strip in Akihabara Japan, but I'm guessing something similar can be found elsewhere.
they are a flat trip that doesn't really like being bent
all the LEDs are in series, so if the chain fails somewhere, nothing lights up beyond the point of failure (which is why I have extra wires soldered on to make redundant paths and get around breakage
I have had some sections of 3 LEDs where one color died
All of the controllers I tried have a dimming function, but it fails to work when I use the fade dimming patterns, which means they are full bright, suck battery and blind others. I've therefore had to add a 2nd voltage regulator where I can just dim the voltage sufficiently so that the current is then also capped by each color string and therefore the brightness is controlled (you cannot limit the global current fed to the LED controller because you don't know whether it's all fed into a single color, or shared amongst 3).
Of course the last thing is that all the LEDs for a color are in series in a single circuit, so you light up all the reds, or all the blues or greens, or none. You can't turn on one LED individuallly. This is where the next solution comes in.
ESP8266/Arduino Controlled Neopixels
To fix the issue of not being able to have custom multi color LED patterns, where each LED/pixel can be controlled separately, the solution is neopixels (aka WS2811/WS2812/WS2812B). Each LED/pixel is controllable separately, which is done by a computer, in this case the ESP8266 can run my own programs to control all the LEDs.
The ESP8266 is a 3.3V based microcontroller for low power use (good when battery powered) while the neopixels are 5V powered, but thankfully the neopixels can use 3.3V signalling from the ESP8266 while being 5V powered to light up properly. The one thing to keep in mind is that neopixels use some power even if they are not lit. In my case 200 neopixels, take about 120mA when they are off, and 4.5A when they are all lit in white on full brightness.
Neopixels are almost infinitely versatile, instead of having them in single line strips like on my shirt and pants, you can also make display matrices out of them: