Catch-all 'Sockpuppet' checker

[AzzKikr]

I'll freely admit that I don't have a coding-related bone in my body. Hence why I'm opening this one up for anyone to take a stab at.

What I'm after is a fairly comprehensive SockPuppet checker. That is, the ability to check certain aspects of a user account against the rest of the database, and output any matches. Probably in a page in the mod cp.

I was thinking:
- PHPSESSION
- IP Address
- Email Address
- Browser User Agent
- Password Hashes

So, to run this check, I go to the relvant page in the mod cp. I type in 'Test1' for the user, and the plugin runs off and checks it.

It spits back a PHPSESSION, User Agent and IP Address match for user 'Test2', and an IP Match for 'Test3'. Hey presto - I just determined that Test1 and Test2 are the same person, and Test3 could be a flatmate.

Thoughts? I promise much love and admiration for the person who does write it