It looks like all the chips have the same tricky antenna requirements.
3. Atmel AT86RF230 PROS:- Single manufacturer solution, provides software and demo boards- ZigbeeCONS:- Specs on the antenna seem pretty scary compared to other chips; it seems to be a lot more sensitive to interference (or maybe the spec is just being honest )
I have experience doing SMT and QFN parts so that is not an issue.
This issue is that you can buy the RF chip for $2.36 but the module costs $17
Also, those modules are $30 @ DigiKey, the unit price of $17 is for min. 200 units. The modules are pretty cool, a breakout board with headers for the various pins such as ADC, UART, SPI, I2C etc would be a nice platform. You could even make it somewhat compatible with Arduino shields I suppose, although there are only three ADC pins brought out from the ATmega.