I am seriously interested in more information about this approach. I think that right now, there are two modern systems of law: Roman-derived law and English-derived, or "common" law. Sharia law might count as a close runner-up. I think Halacha is well-developed, but not widely-enforced, so I would not count it as a major modern legal system.

David Friedman has taught a course in "Legal Systems Very Different From Ours" in both 2008 and 2010. See these course pages: [1] [2]