alt Hacker NewsA 5000 foot long roll of plastic is common. Here is a 50 inch wide roll that is over a mile long which costs $400:
https://www.mcmaster.com/19575T43
Or here is a 20 foot wide roll 1/10th of a mile long: https://www.uline.com/Product/Detail/S-20063/Plastic-Sheetin...
Based on the cost of the roll from McMaster, a wider roll with the same cost basis would be $2000.
An experimental setup, including the land and a new used steel construction could cost less than $500k. Someone could throw a couple million at it to control for humidity, temperature, airflow, etc, with all sorts of variety, and it could be a lot of fun.
If something like this could be made safe, I imagine there are applications in security and process safety in places like nuclear power, water treatment, any facility where you want to restrict access in an extreme way. I'd imagine that it would never be safe, any discharge is going to fry whatever completes the circuit.