A gentleman of my aquaintance has a couple of pot-bellied pigs. His aren't so small, as he feeds his animals more than the cup of food per day that will keep them tiny. His aren't meat animals, as he made the mistake of naming them and it is somehow rude to eat a critter that has learned to come running to you when you call a particular name.
If you want a little bitty pig, you can simply get a piglet and starve it. It'll remain small. Runty, even.
In Vietnam, pot-bellied pigs aren't pets but food. They don't grow so large as Americans are used to their pigs growing, but they do get larger than your average lap-sitting animal needs to be.