That in part is why I suggested Ubiquiti, they make WiMAX and Wifi routers for MNVOs in the 3rd world. So not only are they enterprise grade they are actually ISP grade routers for almost nothing. The only reason I wouldn't carteblanc suggest them to everyone is that they are difficult to configure unless you are either CCNA/ENT certified or familiar with setting up ARP and Routing tables as they have no default firewall whatsoever unless you program one yourself or provide one. The idea is that you would use a Juniper or ASA grade firewall and use their APs for mesh/wds networking.
Disadvantages aside they are the best APs money can buy short of Cisco's Aironet series. I cannot stress how bad *** they are, you just can't find waterproofed, 1000mw+, bi-directional & parabolic APs that have PoE capability of that quality anywhere, much less for $100 or less!