I'm mindful of the link, but at present can't say what exactly the
result will be :)
I suspect this will need to be explored once a more fully worked-out
l3draw is finished. Possibly coffins will be used instead of nodes ...
For l3draw, it does make a kind of sense to hand-off typesetting actual text to the coffins module.
For absolute positioning, I wonder whether it might be reasonable to have implicit coffins (with nothing inside them, but with poles other coffins can be attached to) for the page and/or text-block.
Then again, creating these might be functions of the eventual L3 successor to the geometry package. (Headers and footers and margin notes are all going to be in coffins, come the day—right?)