tl;dr: The xscreensaver package has a program that does something very like this. It's open-source, and works on both linux and OS X.
Then just open a terminal full-screen, apply the plug-in and enjoy your vintage computer.
For best effect, change your font to a VT-100-like one (I prefer the 3278-like one, but that's a taste thing).
BTW, how hard is it to write a Compiz plug-in?
tl;dr: The xscreensaver package has a program that does something very like this. It's open-source, and works on both linux and OS X.