Gosh, I wish this had existed a year ago; I spent an absurd amount of time creating a system for print brochure typesetting in HTML, that would iteratively try to find viable break points (keeping in mind that bullets etc. could exist at any time) that would ensure non-orphaned new lines, etc., all by using the Selection API and repeatedly finding bounding boxes of prospective renders.

It works, and still runs quite successfully in production, but there are still off-by-one hacks where I have no idea why they work. The iterative line generation feature here is huge.