I would say no and IMO thats a terrible idea hence why Ford didn't do so, the pump draws quite a bit of power and so the reason for the relay, it will also run permanently with a switch, it doesn't with the relay.

The switch will need to be a up to the job as your average switch will break down which could have disastrous consequences not just electrically but to the engine as well! It's not good practice to fiddle with anything fueling wise, I guess you want it for security purposes? If so there are far better ways of immobilizing the car.

Martin