Working at a Cadillac dealership in West Texas several years ago, we would see alot of rodent damage to cars kept in rural areas. They would chew hoses, wires, insulation to make room for their nests. It seemed worse in cold weather. One car came in with a red powder sprinkled all over the engine compartment. I asked the owner what this was since I didn't feel like accedentally poisoning myself. She said it was ground red pepper, the rodents would walk through it, then lick it off their feet, it would "burn" their mouths and they would run off to find water and not come back. I thought this was a novel idea to say the least, but, she claimed that it had been working for several seasons. Don't know if it will work for you, but, it's not poisonous, it's cheep, and it could give your brick that "Southwestern Feel" so many people looking for. :)
LOL
Rick