This is my preferred method (now!). Also very simple to write a couple of lines of JavaScript to target P and H elements and replaces the last space with a non breaking space.
Please do this at build time instead of shipping to clients. You'll slow down page rendering, introduce a repaint, and now require a script. Considering all browsers will be doing the exact same execution, it's needlessly wasteful.
Same thing applies to client-side syntax highlighting and LaTeX.
But a CSS method is very welcome!