Cringely has a good article about rolling your own DSL. At some point though it needs to be connected to “the real world” or “the real internet”.
http://www.pbs.org/cringely/pulpit/pulpit20010823.html
My interest is more along the lines of setting up an undercurrent.
Imagine I have a 2 mbit ADSL line (whoo baby…yeah). why don’t I route it onto an undercurrent network which uses “dry copper” to transmit to Kieran’s house. He piggy-backs on my DSL and it also means that if we need to share files we don’t have to resort to stupid zip disks or crappy 56K modems.
Imagine everyone in your neighbourhood had a copper wire leading to someone elses. You could daisy-chain huge networks together and deny BT the several thousand they would demand for the piddle-all service.