How to build a presenter's confidence to depart from "overhead slide" presentations

Every day, I am working hard to convince my clients to switch to a presentation format that no longer resembles the hand-written overhead slides we used in the early 90s: lots, and lots, and lots of slides, pushed forward by remote control, big pictures, big fonts. The slides become the background animation of a speaker's performance. The best way to do it is by using an internal meeting, a low-risk setting to try it out. The annual company gathering, the annual sales rep conference, these are all great occasions. In these presentations I will use humor, images, and concepts that would never make it to an external presentation, but once the presenter has gone through the experience she is usually "sold". The way back to dense boring slides is closed. Subsequent external presentations will be more "serious", but never boring. One more member of the tribe.