Lately, using mini-frame, I have realized a very liveable approximation
of what I had in mind. While normally I work with a maximized emacs
frame, I attach here pictures of a much smaller frame, intended to give
a sense of my current mini-buffer experience.
A notable feature of my current implementation is that I position the
minibuffer over the frame's title bar. Positioned thus, a one line mini-
buffer does not obscure any window content. The downside is that,
in order to position the popped up mini-buffer frame outside of the
selected frame's native boundaries, that popped up frame must be
made parentless. That, in turn, has some rough edges.
Were I able to position the mode-line at the top of each window (an
arrangement whose virtues on a large screen I have argued before)
then I would make my selected frame the parent of the popped up
mini-buffer. The mini-buffer would have to remain within my frame's
native boundaries. But that would be acceptable because, with the
mode-line at the top of each window, it would be one or more mode-
lines that got hidden, rather than any actual buffer text.