sub and sub-sub item organization system
If you can only have one Parent article, add a column and call it 'parentArticle'. 

ALTER TABLE table_name
ADD parentArticle int


This will link to the article id of the parent article. You can then have as many depth as you would like. 


  I would like to be able to shift a set (articles and all sub-articles)
  under the domain of another article with (relative) ease.


You could then add a 'category' column and a category table or, to keep it under articles, have a master article named after its category.