I have never heard of them doing any Skype interviews. That never really seemed like an option as I was going through the application process. I can't imagine that schools would do a Skype interview unless there was some sort of extenuating circumstance that prevented you from traveling for the interview. Like JR42, I too think it would be difficult to commit to the school without seeing the facilities and interacting with staff/students. If you do ask the schools about it I wouldn't mention that you are curious because it would be convenient for you. It makes it sound like you don't care enough to physically go to the school for the interview. Good luck!