It might be possible to modify your wiring approach such that you could get what you want with X10, but it would be complicated and probably more expensive than just using Insteon. The only approach I can think of would involve using modules inside the lighting (or inside the current switch box) and using modules to transmit PLC commands rather than locally/directly controlling the light/device. In other words, use modules like the XPT to send commands and use XPDM (dimmer) or XPFM (relay) to control the device or lighting. You can use any kind of PLC control to turn on the lights/devices you want (RF or PLC transmitters).
This will NOT give you a 2-way communication to your modules, however, since there is no local control, all commands would be visible to your CM15A. So, as long as your communication on PLC/RF is 100% reliable, you would have knowledge of what state devices are in. If you lose power or your CM15A goes offline for some period of time, things could certainly go out of sync, though.
IMO, if you want reliability, Insteon is the way to go for local control since it transmits it's local commands on PLC so CM15A can see them. They are many times more expensive than X10 but I can say that the one module I have installed is much better look/feel/quality than WS467.