Yes, you are right this is exactly an RC transmitter/receiver using Arduino.
On transmitter side there is: Arduino Diecemilla + Xbee Pro
Or receiver side there is: Sparkfun Wee + Xbee.
Trasmitter takes input from joysticks (4 currently) and send it to the Xbee.
Receiver takes data from the Xbee and control servos through regular pulse.
I used my own protocol between the 2 Xbees. It allows many possibilities with high precision, at least 10 bits per channel.
Regarding interference risk, there are pretty low. First Zigbee is already used in some radio systems (XPS for instance). Then, when it starts, the Xbee choose a "free" channel, and then emit with its own PanID on that channel. This greatly limit the risk of collision between 2 transmitters.
Regarding Range, the XBee pro allow more than 1km range. I have not tested myself, but so far it works fine as you can see on one of the video on my blog.