For one of the school projects, I needed a PCB that isn't rigid. After a exchange of emails with someone at DuPont, I received some samples of Pyralux. It's basically Kapton tape covered in copper. I used the toner transfer method to get my circuit onto the copper and Ferric Chloride to etch it. As I've gotten older, I have become more cautious and careful when working around potentially hazardous substances. Having said that, I spilled FeCl all over my desk.
The sheets of Pyralux that DuPont sent me are 18" in length. It does come in roll form though. I'm thinking that one could make some kind of giant flexible creation with this stuff. Maybe a very large lighting application; something for a Vegas restaurant . Pictured below is what I did with it and used it for. It's essentially a glorified mounting substrate for some FSR.