What is special with your exchange model, as you say Next-generation exchange, Bitstamp has gold bullion's available for withdrawal from 2015-2016, so it isn't anything new???
How do you plan handle legal compliance as you are planning open digital bank? You need payment institution license, Coinbase acquired license not long ago
They need to acquire first those legal documents before anything else. So many projects have tried and attempted to lure users with the use of gold, but sad to say, most of them are scammers. We will see how will this project provide all the necessary legalities here. Else, this is just another crap one.