There are switches made by "smarthome" which sends out it's own house code / unit code, followed by an "ON" command, to indicate to a home automation system system that the switch has been turned ON locally. You can then use a controller like X10's CM15A with AHP to turn on any number of other devices.
X10 Inc makes lamp and appliance modules which will do this, but they do not have a wall switch which will send a status indication.