Descending renotes (a la Tumblr)

[aquariusdev]

If I were to start a Misskey or Misskey-derived instance, and I wanted to change the renote tool to place quoted posts above the added blurb, and then wanted to let both renote and blurb be renoted by another user (and so on), how would I make that change?

I'm also asking this in light of the announcement that Tumblr is working on joining the Fediverse, and am interested in how Tumblr-style reblogging would appear on readers like Misskey.