ive met a potty as a pet, he was wonderfull, housebroken, and better trained than most dogs ive met.
he was fairly large (adult male vietnamese), and he slept in a 48" dog crate, he was origionally trained to a large doggy door, but got too big so they quickly trained him how to open the sliding glass door which was outfitted with a strong rope pully and left unlocked when someone was home.
he was a big boy though and could have easily HURT someone, his people were awsome they understood him wonderfully, they never put him in a situation where he felt the need to defenc himself, and they could read him wonderfully, when he was having a bad day they knew how to react and when. (adult males can be a little testy and have large tusks)
Pigs are EXTREEMLY smart, they put dogs (and some people) to shame.
because of this i personally feel they dont make good PETS, instead they MUST be thought of as a companion, they require a different kind of home than most pets...
but they make absolutly wonderfull companion animals.
they are also VERY clean animals, (despite the popular image of them rolling in the mud lol)