What about these dirt cheap ZigBee dongles offered for 10 Euros on ALI?
These dongles are mainly based on the TI CC2531 module and it would be nice to have a working solution for that. It seem some guys in the Openhab community made some progress here. There is a Java driver which appears to rule them all - https://github.com/zsmartsystems/com.zsmartsystems.zigbee. Well, apparently that’s just the client part which implements the serial driver communication. The tricky bit perhaps is to flash these dongles with the right firmware which is said to be available on the TI web site. Does anybody have experience with this?
This may also be interesting: