There are at least two applications built in as standard xscreensaver modules that do some of this already - they're actual terminal emulators in their own right. One is
phosphor and the other is
apple2. On my machine I can, for instance:
/usr/lib/xscreensaver/apple2 -text -fast -program /usr/bin/sh
And the xscreensaver module opens its own
sh and it works. I wouldn't call it pretty, but it works. Here are some usage examples for
I can do this with
/usr/lib/xscreensaver/phosphor -scale 2 -delay 0 -program /usr/bin/sh
If you don't have the xscreensaver package installed it's bound to be available via package manager. Give it a try.
Both applications support multiple configuration settings - and both can draw on the root X window. It may be you can paint the background you desire with something like
xv and get pretty close to the same result.
Of course, according to this you can just buy that Cathode program for linux and that would do the trick, but I'm a little dubious as it seems the last update there was a couple years ago and the try free link seems to redirect to itself.