Video from one slide to the next

I had the same question as you and saw you had just posted it. I have looked and it seems that it is not possible to have video continue between slides. HOWEVER, depending on what you are doing, you CAN create your presentation in ONE SLIDE and use your BUILD ORDER to make elements move in and out on that one slide, and make it look as if they were different slides... then the background video continues to loop forever.

For example, I am creating the visual elements for a Wizard for a local production of Wizard of Oz. I want the fire in the background to be continuous, but each line the wizard says be controlled via a cue... So I have created a different video clip for each line of a floating head. So then each cue becomes a click, and then there will be no overlapping of lines if the timing gets off. A simple dissolve between individual videos makes it nearly seamless. I have created the head with the background alpha-ed out so the two video elements (head and fire) look like one video, but am able to control the timing of just the head. It works out VERY well. Tedious... but worth it.

In other words, I doubt are going this extreme and I doubt you needed to know all this, but the point is it works for me... it should work for anything.

Hope this helps.