this space will discuss the issues that could help in building an affordable wireless ISP for rural and remote areas (preferably using non-conventional approaches).
all the best to us.
let’s discuss and deploy 
http://forum.mikrotik.com/t/start-wisp-5000-customer-network-design/97366/1
#1 - Hire an engineer, especially if you’re looking for “creative” ways to do things. “Creative” solutions may work, but doing things in a non-standard way can really come back to haunt you.