Most gun shops that I’ve been to already carry some type of locking container for storing guns or valuables. The real trick is convincing millions of gun owners to use such devices. The habit of leaving guns and particularly loaded guns in places that are easily accessed by unauthorized individuals seems to be problematic. When I three year old can access a firearm inside a vehicle and shoot herself in the head, you’re going to have a difficult time in the court of public opinion that the gun owner was acting responsibly.
Edit: A simple tool box from the hardware store with an included lock would fit the definition of a safe storage device.
Edit: A simple tool box from the hardware store with an included lock would fit the definition of a safe storage device.