Can we have custom permissions to view member profiles?

[Hilary]

Here's what I'd like to achieve:

Free, public forum: all the world can view your profile. It displays the basics - your name, your website... but not your instant messenger IDs.

Paid, private forum: other members of this same usergroup can see the hidden parts of your profile.

In other words: make elements of a profile available for everyone to fill in, but only visible to members of a certain usergroup. You can see why it'd be useful: create more of a sense of community for your paying members, but don't ask them to disclose private contact details in public.

Is there already an add-on for this? I searched but couldn't find anything. If not, does anyone want to create one?