well, for starters: for the vid, you'll need a static background image, then you'll be needing animations of plymouth units.
Since this campaign is about a group of renegade plymouth people, i think the intro could portrait an attack between them and the original plymouth people. Let's say plymouth lynx come in to destroy a plymouth base (with a different color set: renegades is playing yellow, original plym uses default red). Then maybe the yellow tanks can come in and a fierce battle starts between them,, then showing a logo of "Renegades" .. the end