Yes they are called skinny pigs. They are more common now, i think they originated from the scientific world and gradually got kept outside in the community.
We don't have show classes for them yet. They are quite fragile and must be kept indoors because they are hairless.
I can't really see the point of them myself except for the obvious use in the laboratory, i think there they would be used for skin tumour work. Usually these type of animals have immunity issues too and comprimised immune systems, so not my cup of tea, i like big robust animals that will live.
I can see some would be attracted to the unusual quality of them.