Hi Kaiki:
We did ported the SMAC to the MC13192 Zigbee transceiver for a HCS12 processor. Other than minor changes for register names (SPI module), the port was not difficult at all.
However, IMO the SMAC code quality is not very high, because relies on reentrant interrupts that are very delicate to balance, and could lead to deadlocks and data corruption, if the code around the SMAC is not careful enough.
So, 'caveat emptor' (buyer beware....)
Regards,
Alex