True dat.
However you still have the frequency problem to solve, plus the difference in plugs and sockets. Seems like a lot of work for little return.
People interested in these products are probably willing to put in a little extra effort. The frequency problem for Standard X10 (like the touch screen) is solved with the WGL V572AE transceiver. For the X10 Security devices, we'll probably have to wait until WGL comes out with a 433.92MHz version of their new V572RF32. And these are all wireless transmitters with no plugs and sockets to worry about.
My take on these products:
Touch screen - Looks like it could be fun.
Glass break sensor - Not very practical as you'd need one for every separate pane of glass.
RF Extender - Not needed if you have a decent RF receiver or transceiver.
Gas leak sensor - Seems to be out of production
SD10 Smoke Detector - Not a very full featured product. It lacks a heartbeat signal and doesn't transmit a low battery indication. (The SD90 Smoke Detector is much better.)