The 007 he drew on her hand could have been misinterpreted or it could have had a different meaning than what Meredith thought. Perhaps he just did not think he could face a goodbye. Maybe Izzy's near death experience wasn't a legitimate NDE and was simply a result of the drugs on her subconscious.
Of course, he could well be dead. I guess I've just seen too many TV characters come back from the dead to ever truly believe one of them is dead especially if there is a possible explanation, such as George's body not being reconizable.
Plus there was the last scene with the lady whose life he saved that I can't remember exactly but there was one point during the conversation with her outside of the hospital that left me thinking she was talking about someone who did not sound like George. If I remember correctly, I believe that for some reason she was never shown an actual photo of George.