I've been looking for and at solutions for using org-mode as the markup language for a static site generator, and none of the ones I find do what I want. org-mode has a builtin exporter that can build whole websites, but it is very barebones. The only real solution I know of is Hakyll with Pandoc, which is what I'm playing with right now.
I wish we had something like CommonMark for org-mode, but the overlap of people who use org-mode and don't use Emacs is probably extremely small, so it's not like there will be competing implementations outside of Emacs.