Local Community

Even the most rural community has residents with money to invest. To give you an example, a 200 person rural community in Wales, UK was able to come up with £150,000 of equity/loan financing within months of starting their project from local residents. The economics of a gigabit fiber network are so good, that finding investors isn't usually a problem.

In broad terms, a functioning stable gigabit network is worth around $5,000 per subscriber if the network were to be sold. Assuming your community network can be built for less than that, then there is a solid potential equity return in the future.

Loans are fairly easy to pencil out as well. Out of whatever you charge your customers, if there is $50 left over every month for loan service, that's $600/yr. At that rate, loans can be fully paid back with a few years. More if your monthly fees are lower.

The point being that it isn't too hard to put together a compelling business case for financing a network, either for review by bank or community members.