Not necessarily a drug interdiction question, but a question I often ask is :
are there any dead bodies, bombs or bazookas in the vehicle? I have found that if someone is trying to hide something they often don't realise you are asking such "unusual" questions and will be serious in their replys. People that often have nothing to hide, will laugh when you ask the questions. As with everything, it doesn't always work, but I have found it useful.
I took a fletc class at yarmouth pd with det. peterson, real good stuff. The dept has a good training center, and i know det. peterson said he was hoping to organize a full drug school (1-2 weeks as opposed to the 3 day school I went to) sometime this year. Keep checking http://www.yarmouthpolice.com/train.htm for the schedule.
I took the 3 day FLETC class at the Vermont State Police academy in November of 2004. The instructors were a DEA agent, a Deputy Chief from Illinois and a Detective from the Washington State Patrol. FLETC also has a week long course which certifies students to teach the 3 day class.