Check out the "Event Router" from Event Timing

http://www.eventtiming.com.au/...0Event%20Router.html

Craddlepoint has routers with built in load balancing of multiple cell cards, 12 volt powered and sells a number of different options and power supplies (auto, 120, etc). Add a long range AP like a 12 volt powered PICO station and you can send wireless 10km no problem (we've tested well over 3 miles).