wysiwyg and light-markup are oil and water

[mofo syne]

I see. While I prefer working with the typical 'left screen is input'
and 'right screen is output', I do get a bit irked by the amount of
screen re-estate it takes.

Perhaps we can drop the wysiwyg and stick to input/output model, but
maybe with this twist:

Place the input screen on the top, and the output screen on the
bottom. Input takes vertically 20% of screen, and output takes
vertically 80% of screen.

A red 'box' in the output screen shows where the part that the input
screen is showing.