The first piece of this puzzle is BIB. That's the Boinc International Bank.
This would be setup so anyone running Boinc can signup and create a bank account. It could be a savings, checking, money market or anything else. You might want to have more that one. Some of them would earn interest. Using a similiar process to what the stats sites use, your daily credit would be added to your bank account(s). Your current credit would not be added. You would be paid in the local currency for whatever projects such as :
Milkyway = Boinc Dollars
GPUGrid = Boinc Euros
CPDN = Boinc Pounds
You could choose to leave them in the currency paid or have them automatically converted to the currency of your choice upon deposit using the current exchange rate. Like real life the exchange rate would be governed by supply and demand.
You could even have a mechanism for Boinc loans for a price.
Ok, we have Boinc money but what do we do with it? You could start with currency trading to try to make more money.