Catholic Eye Candy cheats a bit by including the Ethiopian Orthodox Tewahedo Church’s underground stone churches in Lalibela as Catholic art. It’s worth fudging the self-made rules, I think. If you haven’t seen pictures of them before, check them out!
If you’re interested, Wikipedia’s got a good primer including a good quote from Fr. Francisco Álvares, the first (Roman) Catholic to stumble upon them – in his account he swears by God, because he fears no one will believe his story otherwise.