I am willing to write a draft for i;unicode-casemap, but I think that
it belongs in the same document as i;ascii-casemap.
I disagree and it may not be possible anyway.
Disagreement: That document defines a registry and registers the
preexisting collations (those from RFC 2244). That's a fine scope for a
document, and I'd rather not extend it beyond its natural boundary. But I
don't think opinions matter, because:
Possibility: I've already sent that document to the RFC editor, six weeks
ago I think. It sounds like a very long stretch to add a whole new
section as an RFC Editor's Note, particularly if that section is outside
the document's scope as I explained it to the IESG.