Private/Public/Friends visibility on profile fields

Right now, the first/last name profile fields have a public/private/friends visibility set on them.

I found an interesting article giving advice to social networking sites here: http://www.lifewithalacrity.com/2004/02/my_advice_to_so.html -- one of the things he outlines is the ability to make *any* field in the profile have this setting.

This would be an interesting feature that I'd love to see applicable to any field created by profile.module. I'm not sure how to accomplish this in 4.6, but it seems that in 4.7 with its ability to alter forms on-the-fly this would be possible.