They have ‘old’ whois records on file, you need an account though (which I dont have myself, but is cheap afaik and worth the trouble).
They also list other sites on that same IP number, checked a couple, all protected, you might be able to digg up a real contact there.
Domain is registered through NameCheap. You could contact them and see if they have a 0-spam tollerancy as some domain registrars tend to do. I’d say contact them and try to persuade them to relay a message to the real domain owner (they should have one on file, since it’s obligatory to have real info in the system somewhere) ..