[ubersoldat2k7]

I think that what OP means is, where is all the real currency people have paid for BitCoin, how are those assets guarded and how fast of a conversion from all BitCoins to currency would take.

As I understand, you would need an exchange house, who receives real currency, and puts it somewhere (bank accounts, investment funds or other financial structures) from which the exchange (BTW, who controls the security of these exchanges, how much of cash [like banks] they should have?) cannot cash out immediately.

So, if 10 guys with 100BTC go to an exchange, and trade their BTC for Euros and the exchange doesn't have the amount of Euro to exchange, what would happen?