Probably not. I'm guessing the bank interface is different from the money pouch interface. Increasing the coins in the bank would be no different than increasing the quantity limit of every item in your bank, I would bet.
Extremely doubtful as we can put all coin stacks in our much safer RS3 coin pouch. Why risk accidentally losing coin stacks while making our bank smaller with multiple cumbersome coin stacks when we can have a bigger and safer bank with every gp in our RS3 coin pouch?