Really good interview transcript with Brad Bird covering many things, not just Ratatoiulle… check it out.
dvdtown.com/news/a-qa-with-brad-bird/4908
He also alludes to the added chef’s hat at the end of the home video release (not specifically, but he says):
“…I did the same thing with “Ratatouille”–the home version actually has improvements that the movie didn’t have…”