AIGAC member, Adam Markus, is speculating about and researching LL.M. acceptance rates on his blog. While he realizes that his LL.M acceptance rate numbers are estimates based on a shaky "formula," he also has in his most recent post reflected numbers that he received from UCLA and Michigan’s LL.M. programs. In summary, Adam’s estimates and the numbers received from the schools indicate that the LL.M. program at a given school has a higher acceptance rate than the JD program at the same school.
The latest National Jurist provides a complete listing of US LL.M. programs along with the article "When an LL.M. is Worth It." The listing divides the programs by specialties. The article discusses the pros and cons of that fourth year of law school and tuition. Unfortunately the Jurist web site has not yet posted this issues articles.