I watched an opera a few days ago in Tel Aviv, where the singers were performing behind a perforated projection screen, and in front of another regulator projection screen, which created a very interesting stage backdrop. Here is an idea for a presentation set up: put the presenter literally inside the slide.

In the image below, you can see the 2 screens. The battlefield background is a regular projection, the barrels in front are semi transparent. I googled for another demonstration of this stage setup: