Gnomon have a lengthy video from their school of visual effects where the team that created this second trailer for Warhammer Online detail the process involved in that very act. Here is the Youtube Vid of the trailer itself, though you see it in the full presentation on the Gnomon site as well. So dive over and see the creative supervisor level team from Blur Studios show you how the cinematic trailer was done - awesome.
It is cool to hear them talk about changes (esp from one trailer to the next) with things like their shift from 3dsMax to XSI etc. Storyboards are just awesome - I love this part of the process and it goes on from there in great detail over a full 2 hours of presentation. This kind of thing should be compulsory viewing for anyone interested in this field.
Just for fun, here's an image from the event via the same Gnomon pages showing a squig and its crazed gobbo rider.
[image from the Blur cinematic trailer presentation via the Gnomon site]