interesting idea and would be interested to see how this works out. In previous authorities, where Members were open to 'constructive' criticism, we had peer review Members sit in on OSC meetings and meet privately with Chairmen after the meetings to provide them with feedback. This worked quite well and might be an alternative for you, or something to do in addition to this.
One possibility on the video front would be to obtain some videos from the Parliamentary Select Committees, they are all available from the website (http://www.parliamentlive.tv/Main/Home.aspx)
so you could identify some examples and just stream the relevant bits into your session?
Would be interested to hear what you do.