I still have X10 in my house and I use it every day. The living room ceiling fixture and upstairs hallway are on a 3-way switch, and the dining room chandelier is on a single switch.
I used to use it, but a cheap DLP projector would block the signals. I then moved to this automation hardware made by a company called AMX. You write software for the controller and can design screens for the touchscreens that interact. There are tons of add ons and a lot of it is cheap now. It can do simple TCP/IP IO on the network, and the controllers usually have at least 6 RS-232/422/485 ports. They can do digital IO, IR blasting (with a database system of codes for devices) and all kinds of other stuff including their own rs-485 bus that links all the stuff. I scaled it back, but I used to use it to push over serial and TCP to Cyclades PDUs and Baytech PDUs for my AV components. In our hackerspace in Norfolk I ran the lights and arcade games on PDUs tied to AMX along with video and audio matrix switches, the projector and plasma TV and RGB LED lighting on DMX-512. It's just so damn flexible. At home I currently only use the AMX system to remote control Z-Wave plugs via the RS-232 to Zwave box. Mainly for my arcade machines and pinball machines. You could do the same if there is a RS-232 to X10 box of any sort. Maybe some of the smarter controllers can do it? I made one of my AMX interfaces a bot that joins an IRC channel, and I can read the Zwave garage door status and outlets and stuff, but never figured out this Zwave box that is reading the current on the main wires in the breaker panel. That one escapes me. There was a Crestron controller at the swap meet. If anyone buys that at the next swap meet hit me up and I can give you the software to develop for it. But I know nothing about it, I'm an AMX fan cause of the flexibility. Friends told me I would be dissapointed with the Crestron stuff, can't do IRC bots and stuff with it as easily.