-Proof-of-Used-Bandwidth: the more Internet bandwidth a user invests, the more likely he is to become a block producer.
This is terrible idea that will make only rich people and big corporations with biggest internet bandwidth as block producers, and people from countries and areas with low bandwidth will never be able to be block producers, and that is not fair at all and it will lead to centralization.
You would be right if the competition would be global. What I'm proposing is many individual blockchains, where blocks in any particular blockchain can me produced *only* by nodes with Internet bandwidth originating from a geography particular to that blockchain (for example, from a specific country). Within one country or even a part of a country, dedicated bandwidth prices converge above some price level.