A few days ago, I commented on a couple of cases involving conduct outside the practice of law. See here. I mentioned the inconsistent decisions in Illinois involving dishonest conduct when not related to the practice of law.
In yet another story related to this question, the Legal Profession blog is reporting on a case from Oregon in which an attorney was disbarred because of conduct as a business partner - not as a lawyer. The case, again, takes the position that the conduct outside the practice of law shows the attorney is not fit to practice law. I think this is the proper approach to the question, and the reason the Illinois decision in In re Karavidas was wrong.