There are companies you can hire to put their information in the domains for you, and they claim only law enforcement will force them to release the info. But whats the point? Do like the others have said. Register a company out of state, get a business phone, or if you're really cheap, a jConnect voice mail box/fax which forwards all voice messages right to your email. Put your mothers name in the WHO IS info or your arch enemy from high school. It doesnt matter.
Worst case, put all bogus info inside, and you'll only be contacted by the registrar if someone tries to contact you, can't, and complains to them - but theyll send you a courteous email telling you to update it. Again, you really want a way for people to get you indirectly. You never know who is offering to pay you $500,000 for your domain, or what lawyer is sending you a nice C&D hoping to resolve the issue via a quick email vs. rolling up their sleeves and creating a real suit. Because once they put their sweat into it, theres no turning back, and you're screwed. So spend a few measly dollars and do it right.