What about box track sliding door hardware? We had that on our horse stalls when my folks had that place. The box holds the wheels straight, level, and can be plenty strong to hold up a large door. Little stops mount on the floor to keep the door from coming off the ends and one to keep the door from swinging outwards and had a roller in it to help move it along. It is defintiely not hidden hardware, but in black with natural wood looked pretty nice. I think your door weight may determine what hardware you can use as well.
