About the wireless approach, Monkeybrains (https://www.monkeybrains.net/residential.php) in SF seems to do this. I believe I read somewhere that they're planning on replacing the wireless stuff with fiber for areas where they have high customer density. They're awesome, the service is good (except when it rains. Thanks california), it's cheap ($35) and I've been pretty happy with it.

I wonder if that could work to bootstap an isp. Obviously the wireless thing won't work in less dense areas and is subject to weather but maybe a successful business in the city could provide enough capital to expand to the suburbs.