A big - nay, huge - problem with BPL is that it's generating more interference than is strictly legal. It screws up the 10 meter Ham band completely - these are licensed operators with a right to that spectrum, who routinely use it in the service of the community. Power lines were never really designed for transmitting data - they're not well shielded, putting anything other than a 60Hz sine wave into the system creates huge problems, and lately, they seem to have enough trouble just carrying power. What's really needed is... something else.