What's Required to Give Users 1 Account with 2 Profiles: 1 Anonymous (UserID) & 1 "Rea

This might seem a weird feature, but here's what I'm after:

Studies of participation in on-line discussion behavior consistently reveal 2 seemingly conflicting dynamics: limiting user anonymity decreases negative behaviors that like flaming, piling-on, trolling, stalking, and lurking, generally leads to more thoughtful user-generated reviews and commentary, and a more positive overall community atmosphere. However, the lack of anonymity likewise tends to suppress minority or opposing viewpoints contributing to group-think, homogenous content, and less exciting on-line exchanges.

So my idea as a publisher is simple: Give users the ability to have 2 faces - both a "real" and an anonymous one - still connected to just one user account. Give them the ability to choose which profile face they're loggin-in with. And give the site admin the ability to create some controls like ability to create real-only or anonymous only forums, groups, content, (I realize this part is fairly easy) and the ability to set some constraints governing the balance users must adhere to - ie no more than say 60% anonymous for example.

Can someone give me some guidance on what the hack required to do this entails? Which, if any, of the live support sessions might be best able to give me some direction, etc...