You're mistaken if you think full reserve banking somehow doesn't "stretch" the money supply. Let's say I deposit $10K in a "full reserve" bank. The bank then loans it to someone who buys a car. The car dealer goes back to the bank and deposits the proceeds of the sale. Another fella comes in for a loan and the bank gives him dealer's $10K. He then goes to buy a car. Now there are 2 cars bought with "my" $10K. And this can go on ad infinitum. So there is nothing superior about full reserve banking. The only thing you're doing is preventing me from getting my money unless the guy who took the loan pays it back. That will surely incentivize people to keep their money in a bank.
What you get is interest fit allowing your part of their reserve to be used for loans. It's why certificates of deposit have a higher interest rate at /r/ActualMoney banks.