I hate to revive this thread but I have a site I need to take to production soon. If it helps anyone, in the meantime I used this plugin (github – Limit Upload) to limit the number of uploads which works for me as of WP 3.8.
Now the issue for me is still enforcing the ‘Uploaded to this post’ selector in the media uploader. All the solutions I’ve found are javascript based and trigger after the uploader already starts loading the entire media library.
