Seeing Red

Ive been farting around GW since its release and have done quite a bit of trading. I came across this guy wanting to buy Red lettered items. He said they existed and he's seen them. I check with other people and they said that red lettered items didn't exist. Could the guy have seen some ultra rare item or is his monitor on the fritz? Basically, Im asking, do red lettered items exist and what makes them so rare if they do?