I built a Safari Extension for my own use and some others might be interested. Basically it extracts the article from a page and creates a markdown draft of it.
https://github.com/ddegner/SafariToDrafts
Feel free to compile it yourself. If there is enough interest I might release the extension on the App Store.
I get a 404 error when trying to access the github repo. Perhaps it is set to private or has been removed?
I can not open that page on github. Error 404 
I get a 404 Error when going to the link you provided.
Still 404 error to provided link.
Very sorry, I forgot to change the repo to public.
It should work now: GitHub - ddegner/SafariToDrafts: A Safari extension for creating a draft out of a safari tab