People do all that for free for random youtube videos, some projects take longer. It's all a matter of will and crowdsourcing is one way to raise money. Also if we aren't charging for people to watch the movie its legal based on my understand of fair use laws in America. Unless japan laws have meaning in the US.
You know it would take years and a lot of money. Forget it.
I was thinking about a comic, manga is very restrained, we'd be able to do colored pages and work with PC which is easier and give much more definition.
People don't care if it's a HD movie with explosion. Proof with the rating of The Last. We'll put all our effort into the story!
A remake of the last chapters and a special comic in replacement of The Last, hell why not songs made by the fandom it doesn't cost much and the internet is full of talented people!
It would probably be the first fanmade project that big but at the same time hella affordable.