Is there a way to direct request for deleted pages to 404 instead of displaying the loginbox? If the article is emptied from the trash bin, this works. However if the article is still in the trash bin, a loginbox will appear and users get confused.
Not out of the box afaik. But you can just create an HttpModule that inherits from UrlRewriteModuleBase, check if the page is deleted there, and do the redirect if IsDeleted is true.