What is the chance that a complete unknown wins the main event?

[NickMPK]

It seems extremely likely that the winner of the Main Event will not be a 'big name' (e.g. top 100) player.

But while none of the last three winners were 'big names' at the time they won, they all had a decent record of cashes in notable lower buy-in events.

You could find Raymer, Hachem, and Gold on the Hendon Mob poker database before they became world champions. On the other hand, Moneymaker and Varkonyi were completely unknown on the poker tournament circuit prior to their win, although they both competed in much smaller fields.

So, if we define a 'complete unknown' as someone who does not currently have an entry on the Hendon Mob player database, what is the chance that a complete unknown wins the Main Event in 2007?