[bdesmond]

Multiple computers running multiple monitors. Each presentation goes on a different one so when you move between decks you just do it form a switcher. Run the playback sources from playback units, switch that too.

In other words you give the presenter a little remote and monitors on the podium and in the stage.

I have been to a lot of corporate events, I have seen this done seamlessly and not so seamlessly. There is also lots of oppurtunity for some fun with a few trusses of intel lights if there's budget.