I sort of dropped the ball on this, but sometime in the last week or two, the first user reached 10,000 reputation on Super User.
That user is John T.
July 15th was the first day of beta, and John -- as of this writing -- has 11,232 reputation. That means in about 48 days, John has produced 234 reputation per day. (Remember that bounties and accepted answers are immune to the 200/day reputation cap.)
Impressive.
It's all the more impressive when you realize that John is a mere 18 years old! (He's also Canadian, but I won't hold that against him.) Looks like we have another lifetime Super User on our hands.
Congratulations John, and thanks for leading the charge to provide great answers on Super User!