$20killionaire didn't have the same ring to it.

Hmm, the atomic integral unit of Bitcoin is actually the 'satoshi', and there are 100,000,000 satoshi in "1" notational-bitcoin. So anyone with 10 BTC or more is a "bitcoin billionaire [in satoshis]".

That must be it.

In the sense that he has more than one billion USD in bitcoins. (No one can own a billion bitcoins.)

No way he has 1,000,000 BTC. Perhaps 200,000.

At the moment Satoshi is still the only Bitcoin Billionaire with several people waiting on btc = $2,500 until they join the billionaire club.

I'm guessing you're the Pankkake from Bitcointalk?

How would you know that? Someone could easily spread the coins across many addresses.

A lot of people on the Bitcointalk forums have made educated guesses, the fact is he still works on his business and charges for subscription to his blog, I doubt he has amassed the largest stash of Bitcoins in the world.

"the fact is he still works on his business" a lot of billionnaires still work on their businesses, if not most. This hasn't been the norm of Bitcoin - most people getting rich just went away with the coins, which is pretty bad. His estimation accounts for the assets he owns, same method as for the fiat billionnaires.

For the other question, there is only one pankkake.