Leave your attorney as the administrative (admin-c) and billing (bill-c) contacts. If you only list your home phone number, how do you expect them to contact your attorney (by the way, if people are calling for seperate domains and they're going to separate reps, then they will not know this).
You chose what number to put in the whois information, don't get mad because someone is using it. If your domains are that highly in demand then you should be off well though to get a separate cell phone, some will give you unlimited incoming calls and now the 3 largest companies give you unlimited calls for $100 and leave that as the contact number in the WhoIs information.
You can also get a low end plan ($20-$30 a month) and just don't answer any of the calls (even turn off the ringer), screen your voice mail (don't use up your minutes, use your night & weekend minutes or check from a land line).
Also, as you stated before, these calls are not illegal and against the national do not call registry since you left that number as a contact number in the WhoIs information. That means that number is a business contact and they are contacting you to do business.