i use the large dog method of intimidating solicitors away as well.
i had a guy come up to my front door once to peddle something (he had flyers in his hand, i never got to talk to him). the main door was open, and the storm door (metal on the bottom, screen on the top) was closed. the dog was sleeping on the floor in front of the door, but hidden by the metal on the bottom.
solicitor walked up the steps to the door, made a little noise on the cast iron railing on his way up, startled the 140# mastiff mix, who jumped up, cinderblock head appearing in the screen suddenly, and let out a huge woof from the bottom of his hind feet, scared the crap out of the solicitor who was last seen running down the sidewalk away from our house.