Hmmmm that gets me thinking.....
I have a couple of LINUX boxes. On one of them I put in a video capture card and loaded up some free security software, ZoneMinder. I split the video (as stated before) and fed it to the RF modulator.
The long term goal is to put up 4 night vision/color cameras around the house. 2 up front, one on the front door and one for the back yard.
I'll get a 4 channel video distribution system and put each camera on it's own TV channel, and feed it into the cable running through the house.
I'll also feed the cameras into a 4 channel 120 fps card in the LINUX box and run zoneminder on all 4 camera. Zoneminder will record video when it detects motion. It will also e-mail, sound an alarm blah blah blah.
Fun to play with.
I'm still thinking about this one, but I would like to have a movable camera that would track and record objects moving in the sky! UFO!!! lol