You could also take a look at the Frsky Taranis 16ch, got this in my Scania T580 and MB Actros.
Have a reciever in both trucks, and change between trucks with a switch on the radio.
Would be nice in a dumptruck and excavator setup
260$ for transmitter with 2 receivers
http://www.rangevideo.com/index.php/...-usa-110v.html