A growing number of people seem to be using one (touch)screen for control of Xlobby and another for viewing content (movies, etc.). As such, I think the ability to send the photo slideshow to a second monitor would be really appreciated -- certainly by me anyway. I know nothing about coding, but since Xlobby already includes X/Y positioning, it might be as simple as including that feature within individual modules, so that one could choose what is viewed on what monitor.
Just a thought...