X10 does not make a motion detection camera. You can use an X10 Motion Sensor, to send an On and Off power line signal. To the cameras addressable power supply. To trigger recording. Maybe a VCR commander.
They do make a combination motion sensor, camera and flood light. Called a FloodCam
http://www.x10.com/products/x10_vt38ac.htmQuestion 2. All the 2.4 GHz wireless cameras share four selectable RF channels. More than one transmitting at a time. There is a good chance they will step on each other, even if each is on one of the four channels. They also share with things like wireless networks and cordless phones.
The new Pro Line cameras, video senders and receivers all use 921 MHz. So again more than one on is asking for interference.
If you need six feeds you may do better with a camera system made to do surveillance work.