That currently does not exist anywhere. The closest thing would be BitInstant's credit card offering but there is no launch date and even then it is unclear if funds sent to the card would remain as BTC and converted as needed or if all funds sent to card are converted instantly to USD.
What you are asking is the "the holy grail" when it comes to BTC/CC and will would require a high level of integration with a very well capitalized company AND a merchant bank (i.e. a bank which has a license from MasterCard or VISA international). It simply may not exist for a long time.
BitInstant already stated that balances would be converted to USD and held in USD at the time of loading. I was really hoping the balances would be held in BTC and only converted when used, but alas, no such luck!
Again just not possible currently. Unless someone in the BTC community decides to startup their OWN payment gateway, then don't expect to see this feature. The only way currently, is to keep USD funds on debit cards. The conversion will always take place prior to the debit purchase.