I am based in the UK and it is exactly how it is charged for on the consumer side, I can choose how fast I want my delivery to be (1mb/s -> 80mb/s) and also the monthly total consumption (10GB -> 20GB -> 40GB -> "unlimited").
I don't see how that's much different than the usual here in the US. You're paying monthly for a connection, variable fee based on speed of that connection, and then you have a data cap. I don't see how that's paying based on consumption.
http://www.productsandservices.bt.com/products/broadband/pac...