Though I have been focussing on Zigbee lately, all that Atmosphericon needs is an easy to use, robust network architecture. There are others out there. SunSPOT from Sun is an interesting project. If it gains traction, it could be a very interesting platform for ambient feedback devices. It’s pretty hardware-heavy, as all Java solutions seem to be, but it could attract a lot of developers, aspecially if the hardware becomes gets more flexible/customizable as time goes on.