You could also consider this is you fancied going down the APM route
http://www.droneshop.biz/multirotors/self-build-kits/f450-gps-quadcopter-self-build-kit.html
http://www.droneshop.biz/multirotors/quadcopters/f450-arducopter-gps-quadcopter-fully-built.html
http://www.droneshop.biz/multirotors/self-build-kits/f450-gps-quadcopter-self-build-kit.html
http://www.droneshop.biz/multirotors/quadcopters/f450-arducopter-gps-quadcopter-fully-built.html