You're going to need professional help.
(If you want free advice on how to do things cheap, try: http://www.isp-planet.com/fixed_wireless/)
You may get some snipets of good advice, but they won't arrange themselves into a solid specification, sorry.
What you are asking for will require professional services from an experienced wireless firm. That's the best way to accomplish things like:
- Hybrid WiFi/U-NII network with 99.99+% reliability
- Per-user bandwidth throttling
- Removing the risk of getting ripped off by anyone who can spoof a MAC address
... without having to learn everything the hard way.
The good news is that you may actually save money by getting the most out of every cell and every piece of equipment.
Matthew Wheeler