I believe the trailer moreless corresponds with the mod's reality - with the longer playtime players tend to build huge castles and armies. Add in the new camera system and the trailer could pretty much become true.
The higher resolution version is indeed quite large (partly because of different video format) on the other hand watching it at 1024x768 is quite a different experience
I don't know how much time filefactory allows for hosted files, in any case I'd recommend to host it somewhere else (bfmeheavens, youtube, 3rdage, etc.)
And yes, there will be another trailer by zachdaddy who will show you some of the highlights of the beta 4.7 so stay tuned for that
The beginning music track is taken from Mass Effect soundtrack (nr. 10, "Spectre Induction") and the other one is called "Moving Mountains" from album "Nemesis" by Two Steps From Hell. All credit goes to them