I think you should forget about Katz and DDL sites as they will never accept this feature.
You should first of all contact WBB admins as it is the only website that has implemented a link protection feature. If the admins there approve your site and whitelist it, it'll be adopted on a large scale by the warez community.
I dont want to sound rude or anything, but the real uploaders aren't there on katz etc or these small sites who are just made for reselling. Go to bigger forums and contact those e.g Warez-bb, the paradox, forumw. etc etc
Its the uploaders on these sites who actually need some type of link protection, cause they are the ones who reupload the files again and again.
So contact their admins and try to work with them, if you succeed your site will get a huge amount of traffic e.g safelinking.net