Some of the Insteon interfaces and some of their software will allow control of both Insteon and X10. Some Insteon switches/modules could be configured with X10 addresses and controlled with X10 software and interfaces. They seem to be discontinuing those, however.
I expect to introduce something (hardware & software) in about 3 months that will allow control of X10, Insteon, UPB, ZWave, etc. from Windows, Linux, OSX and Android.