Right Arm of Zeus,
A few years ago, I did similar presentations to several large groups. My words of advice are to go slow and don't assume anybody knows anything you are talking about. I included a "lessons learned section" and I think that got a lot of attention. I also included a "setting expectations" section that included all the facts and stats about recruiting %s. I included a "myths" section too.
If you want, send me Dialog with email. I'll send the presentation it to you to give you some (hopefully) ideas.