Here is the source code modifications to allow you to run the Atmel Ranging Toolbox on an Atmel ATxmega256A3U-and-AT86RF233-ZigBit module - http://www.atmel.com/devices/ATxmega256A3U-and-AT86RF233-ZigBit-Wireless-Module.aspx.
This was the code that ran on the original demo here:
You can obtain the sources and the precompiled hex from the github repo:
Note you will need an Atmel ICE or equivalent to program the Zigbit as the serial bootloader doesn't work with this.
The Ranger supports much more functionality over the ZigBit modules, such as antenna diversity, USB and many more software features, however this gives you an idea of the functionality of the RTB libraries if you have some ZigBits laying about.