Philips Hue, and Zigbee direct-binding in general, can achieve this if you're willing to use their wall switches. Still works if the hub is offline.
Depends on your definition of "regular switches," I suppose -- but anyone with 3-way wiring (i.e. multiple light switches for a single socket) has given up on "up=on" for their switch.
Depends on your definition of "regular switches," I suppose -- but anyone with 3-way wiring (i.e. multiple light switches for a single socket) has given up on "up=on" for their switch.