There aren't a lot of riffs in Takahata's 1981 movie, Jarinko Chie, but there are a few really good ones. Most of them are later quoted later in Omohide Poro Poro or My Neighbors the Yamadas. Makes sense, you suppose, when you realize that Chie inhabits the styles of both those later films.
Here's one good riff from Jarinko Chie that appears in Poro Poro. I'm not going to reveal the context, since that would spoil a pretty big surprise. I don't think anything is spoiled if you haven't seen this picture.
Oh, and I'm still working on uploading Chie to youtube, sans subtitles. It should be up later tonight.