Leviton also sold the same X-10 in wall transmitter that was made by X-10. HOWEVER, their faceplates for that device also incorporated a status LED, so by looking at the "switch" you could tell which circuits are powered.
I have a backyard set up that has some tree lighting, deck lighting etc, and for control I replaced the original switch that controled a single deck light on the house with an X-10 XPT with a 4 button controller, for each of the backyard circuits I added an in line receiver and voila, I turned a single control point into a full control point. Works great - EXCEPT, more than once I discovered during the day that some of the tree lights were on (cannot really tell during the day) making me wonder how long they had been left oon. The switch gave me no indication of status - RATS!
Then, one day while perusing E-Bay I ran across the same 4 switch faceplate for the XPT, made by leviton, but with LED status lights by each paddle! I picked one up, replaced the X-10 plate with the leviton plate, and now can tell if someone has left some lights on by looking at the switch. I consider this a big improvement, and candidly the plates available on E-bay are no more expensive than the X-10 plates available, but have the added LED. They make then in all flavors (1 switch, 1 switch bright/dim, 2 switch etc)