Building an Non-Wired Network for Pueblos?

wsxian asks: "We recently received a large grant to install a wireless high speed Internet system for our entire Pueblo here in the State of NM. This would encompass about 150 homes and the range from a central point would be no more than 6 miles, but there are hills, valleys and trees so line of sight is not an option unless we decide to drop homes. I welcome any suggestions for technology to look at, what to avoid, security concerns- and most important for us what companies to avoid. If any of you have had real life experience with doing such a scaled project like this, please give your input!"