Oki Semiconductor claims to have the first commercially available ARM-based ZigBee short-range wireless comms platform.
 
The platform is based on Oki's ML7065 radio and Oki's ML67Q4051 MCU for the ZigBee stack and application code. The ML7065 is a 2.4 GHz IEEE802.15.4 complete full-function low-power single chip radio solution with an embedded 802.15.4 MAC/PHY that is suitable for ZigBee transceivers in industrial and home applications such as automatic metering.

The ZigBee stack requires around 44kbyte of flash for an end device and 60kbyte of flash for a controller with 10kbyte of RAM.  IAI provides the multi-platform certified ZigBee software