Very cool! Does anyone know how this is implemented? I was thinking of doing similar by using 'dtach'. Essentially the plan was to start the terminal with dtach, and whenever I wanted to change the settings I would detach, update, and then reattach with a new terminal. Of course, my approach would add overhead if you weren't already running dtach for some other reason.

Essentially it prints out control sequences. Here's some documentation on them. http://xfree86.org/4.7.0/ctlseqs.html

Interesting. I wonder if this works with rxvt-unicode.