Starting to Sketch...
Here are some early attempts in response to the question of what the binder might look like.
These drawings take the back support brace as a model... they usaully involve a metal spine that provides support. They are corset-like and very sturdy. But they might be too stiff and uncomfortable for this application.
You need to wrap the binder several times in order smooth out the look of the chest. The number of times that you wrap effect the location of the LEDs? I originally imagined the LEDs travelling along the center of the binder.
Obviously this is not for everyday use. In fact you would have to dress in a way to showcase the binder if you wanted to be able to see the illumination. Perhpas an ace bandage with some LEDs would be the best place to start.