Im guessing that among the top level restaurants, L'Arpege might be the best for a vegatarian. Im not sure if they have any lunch specials. The chef there is known for his creative preparations of fruits and vegatables. They may have a vegatarian tasting meal but I cant remember for sure. I do remember a desert of a poached white peach and 150 year old balsamic vinager though that was to die for. He also has a trademark desert made from a tomato and some incredible salads.