"Kodomo no Hen"
It's the summer of 2005 in Tokyo. The voices of happy children can be heard. What is the destiny they face...? Cuts to a kid running with his backpack on that looks like Ed, another that looks like Al, and finally one that looks like Winry. Also, in the cast audio commentary in the movie, Paku Romi mentions Edward as being a grandfather.
A live action version of HAGAREN? The place which Al loses himself in as Ed searches for him is...
And, of course, you all know about the other two.
EDIT: Paku Romi WAV clip sorry for the bad quality audio, I recorded it from my TV speakers. ):