If there's any evidence of Naruto possibly dying, it's done through the elements of allusion and foreshadowing.
Think about it, every "Narutoish" character thus far has died far for their beliefs; Nagato for his dreams for Konan and Pain, Obito for his belief of never abandoning a comrade, Minato for his responsibilities for the Village, Jiraiya, again, for the sake of leaf village.
Unless Naruto is the one to change all of that I strongly think that he will eventually die. And on a side note, I don't understand why people think that if the protagonist dies in the end the series automatically becomes horrible, I prefer character death, it has more of a long lasting effect on me.
As far as I could tell, no one has stated that if Naruto died in the end, that the story would suddenly become 'horrible'. The points that were made were that Naruto is a Shonen Manga, and so doesn't follow along the same lines as a Shakespearean tragedy, and really can't be compared as they are two completely different genres. And I understand the point that you're trying to make, but the whole theme of Naruto is to
surpass all those who have come before him and died before him. It *really* wouldn't make any sense for Naruto to go through so much, persevere through so much, only to be killed in the end.