After moving over to deCONZ I have 3 CC2531 USB sticks spare. So I flashed them with the router firmware and added them to deCONZ as routers. They are shown as lights:
Got them plugged around the house direct in USB socket and extended my mesh well 
Just an idea for those with any lying around or needing to buy a cheap zigbee router (mine were about £4 each)
Also the stupidly bright green light on the USB stick is the light - ie you can turn it on or off as a light. May put one in the hallway and use as a nightlight off the motion sensor in the hall (it is that bright )
mb