I'm happy to accept this proposal.

B > A > C > D.

As you'll see on the GitHub thread, I have convinced myself that (C), allowing keywords in traditional record syntax, is untenable.  And I really don't think we should reject (D).

I'm favouring (B) over (A) for simple consistency reasons; the fewer exceptions the better.  Plus at least one person has said the extra generality would be useful.

Simon