Since bitcoin does mutlisig you could do something like this https://bitcointalksearch.org/topic/proposal-for-safe-blockchain-storage-pools-for-exchanges-using-multisig-96391
Wouldn't setting up a 'multisig' process limit the end-users ability to withdraw their own funds without a "teller" so to speak approving the withdraw of funds?
I mean that gets around the issue of someone being able to withdraw funds without the approval of 3 parties in the transaction, but that doesn't stop someone whom gained access to the wallet server authenticating the transactions and their destination even with a forced 2/3 authorization.
So in this method someone would have to manually approve transactions?
I know this topic is a little old but I found it via Google and would like to know if there has been any other similiar discussions/questions posed?