Anyway, it was just an idly amused question. I'm not convinced that
stuffing this down into the tty line discipline is the right thing to
do, but I do agree with your problem statement.
I'm not convinced this is a right answer either. But, short of putting
an extension language for writing such things into the tty driver
(which would come with its own pile of problems), it strikes me as
about the closest thing easily attainable, and it doesn't seem to be
obviously wrong, either. And, based on what I've seen so far, it
sounds as though the closest things to it are the Blit and COMND%,
neither of which is really close enough to give much idea how well it'd
work here. So I think it's reached the point where I should go off and
start experimenting. :)