err consider John Doe... He doesn't give a damn if his bank is open source or not. John Doe is not your target, people who use BitCoins (and I don't mean lemonade selling girl scouts) are your target.

Electricity, Air travel, Internet? Don't you think these were crazy ideas some day?

With Bitcoin ATM's opening up in Toronto where I live, I see things moving fast than even myself expected. Sure, there will be resistance but it's hard to suppress something as revolutionary & crazy as Crypto currencies.

Assume the same John Doe :), ordinary internet user, Never heard of XYZ Open source bank, No idea how it works, 0 control over it. Will John trust his life savings with this Open Source bank?

I'm not trying to de-motivate you or diss you, infact I encourage everything Open Source! It's just that I'm attempting to outline that something out there already exists which solves may be atleast some of the problems you want to solve. Good luck!

The idea & support for transactions like borrowing, lending, escrow and likely all other transaction types that you can think of are already built into Bitcoin & it's design. They are just not being used as of today.

Infact, I would say it's safer to carry out such transactions using Crypto currencies than with a Bank. Please see this video: http://www.youtube.com/watch?v=mD4L7xDNCmA

Satoshi was clever enough to think of all use-cases and he made sure that the design & eco-system would be solid enough to replace centuries old incumbents like Banks. The features are just sitting and hiding there in the protocol to be made use of when there is enough traction & momentum.