Almost every existing md to PDF goes through LaTeX: kramdown, pandoc, multimarkdown, etc.
So far I have only found:
Gimli, but it does not seem very active (last commit 7 months ago). Backend?
markdown_prawn. Not many stars. Last commit 3 years ago.
Kramdown Prawn experimental converter. Experimental.
If you can convert the HTML subset generated from Markdown to PDF well, then that is a solution, but I am yet to find a software that does it properly. For example, PhantomJS conversions break markdown links
<http://a.com>, which show as simple styled text on the PDF, not as clickable links that open on preferred browser, which are generated through LaTeX conversions.
Related: Ruby only SO question.
Why I want this: LaTeX is slow, produces horrible error messages, is hard to install, and is overly complex for the small subset needed for Markdown.