No, we've never had other pets in the house in real life. There was a dog interested in coming in, once. But we would not have trusted him around the pigs. Guinea pigs are social animals, but I'm not sure how much they'd enjoy schmoozing with stranger pets, even if they were fellow rodents.
Of course, "Skrillex" from next door always wants to get in. But there's no way we're letting him in the house.