Let me respond to the 3 previous posts:
jimbo: Well put! I indeed have a solution in search of a problem.
hj: there are never 2 dimmers in a circuit for the reasons that you mention. there are master dimmers, the device responsible for the actual load limiting function (the dimming) and there are remote dimmers that don't limit the load but communicate with the master to instruct it to dim to the appropriate level. To communicate these master/remote combos use one of the travelers hence the wiring is no longer standard (or conventional) therefore standard 3W and 4W switches don't work. The fact that the technology that I describe CAN use conventional wiring is a plus in that the standard 3W and 4W can co-exist - a consumer isn't forced to replace all switches when replacing more than one. I now want to find the BEST use for this technology.
jwelectric: With respect, a Google search of "master slave dimmer switch" produces more pages than I can read about this topic. Described in a bit more detail above to hj. My original question is my entire original first paragraph; I describe a technology and ask for uses or as jimbo so eloquently put it, I describe my solution and I ask for a problem that it can potentially solve. I also appreciate the extra information that you've provided. Let me rephrase the question below and I would very much appreciate an opinion on the technology if it is any clearer:
If there were a dimmer switch (a load limiting switch at either the load-side 3W or the line side 3W - called a "master switch " in all of the Google results and in the Lutron, Leviton, Lightolier literature for their versions of the switch) and another switch in the circuit that communicates with the load limiting switch to instruct it to dim (called a "slave switch" or a "remote switch" in all of the Google results and in the Lutron, Leviton, Lightolier literature for their versions of the switch) that could be used in a circuit using conventional wiring for 3W and 4W switches and could exist in the same circuit with any number standard 3W and 4W switches (in the Lutron, Leviton, Lightolier literature for their versions of the switch they all say that you have to replace all switches in the circuit if you want to replace more than 1 - whereas using this new technology both types - master/remotes and standard 3W and 4W - can remain), what would be the best use for this new technology? Indeed, I have a solution for which I now want some brainstorming to find a problem to solve.