I'm not aware of anything published, but the code is open source, and if you're so inclined you can probably point a clanker at it. The second one is called "redaction" in Mononoke, I believe (obliteration is a different term for it, as is censorship).

You are correct that integer sequence numbers and redaction are both reasonable things to want -- we just believed (for a variety of reasons) that the core should be Merkle and that these things should be built on top.