I want to point out that something like this can only exist once BitUSD becomes widely used. Like it or not, for now bitcoin is good enough.
Their are only 2 things holding us back from being able to be used in this fashion.
1. market depth for bitUSd must be increased.
2. a way to cash out of bitUSD
Btc is only working because it has a much more depth, If you talk to sellers or businesses almost all of them want protection from btc's volatility. 10$+ swings in 24hours is not good for a market place. It quickly turns a profit to a loss or a break even or a huge profit which creates buyers remorse.
If we provide depth they will come.....