LED-Lit Force Sensors

I am attempting to build something similar to a lot of MIDI drum pad controllers, and the QuNeo. I have built a prototype using stock FSRs, but would really like to make my design more compact and elegant. I'd also like to light up my pads with LEDs.

A couple pictures I found in another thread show exactly what I want:


Are there any resources on designing this kind of interface?
What companies manufacture these films with the conductive black material?

Thanks!

Bump... Any information would be greatly appreciated.