Two years ago the Question What is best practice re. handling legal sources with Biblatex/Biber for disciplines other than law? received numerous thoughtful comments, perhaps helping to inspire the
lawcite package (github.com/texcicada/lawcite). As I understand it,
lawcite is intended to be general enough to accommodate any (?) legal citation style and already has at least partial support for AGLC (Australian), McGill (Canadian), and Modern Law Review.
Can Bluebook be far behind?