Possible workshops include Time Management, Conflict Management or Situational Leadership workshops. You may want to consider offering training in a skill that can be shared with their students. Consider a format which allows students and advisors to share ideas. Having a table topic discussion during lunch is one way of fitting an information sharing session into your conference. Each table would have a specific topic.
Advisors can have tables with topics that relate to their specific needs.
Videotape can be used for review or renewed motivation as students get further from the event and begin to lose focus. It is also a great way to create a promotional tape for future conferences and also to garner support from businesses. You can expect students to pay more attention and take better notes when they know they will be responsible for re-teaching the information to their peers. You also reinforce messages of leadership and community responsibility by having your students carry the messages of the conference to those who were not in attendance.