I was re-reading some of the interviews so far. Specifically this one:
http://www.pcgamer.com/2010/12/04/warhammer-40k-dark-millennium-online-a-grim-dark-future/Quote:
It’s not just your character you’ll be customising: mechanised war machines are central to DMO, as they are to the 40K fiction. The game’s first trailer teases viewers, ending on footage of a five-storey walker romping across a blasted landscape. That two- legged monster was a Titan, one of 40K’s largest and most killy war- bastards – and Dave confirms that a player was controlling it. “You’ll use vehicles in PvE, you’ll use them in the general over-world, and you’ll use them in PvP.” These vehicles can be run with a crew, separate players taking on the roles of gunner, driver, and man who stands on top and yells “DRIVE FASTER!”
Or, you can go it alone. “In a tank, you control the primary turret, but you don’t have the full command of all the weapons on the tank. If someone jumps in the primary turret then you might just be driving.” 40K’s grab-bag of lethal vehicular toys makes this prospect a tasty one: the game’s first trailers clearly point at a number of the universe’s iconic battle-tanks, such as the Predator. Handling is pitched somewhere between simplistic and simulation, but Vigil are keen to keep the physical connection: glide toward another player on a turbo-charged bike and you’ll thunk into them: “you can’t drive through another tank like it isn’t there. That just looks weird.” Mike singled out the PvP battlegrounds as a particular hotbed of vehicle use, but wouldn’t be drawn into explaining quite how they’ll work when used against your fellow human.
That suggests to me that the Titan is PvE. Which would make sense, I suspect the player is giving it orders rather than piloting it. Then he goes on to the PvP bit and players multi controlling. But I may be reading it wrong.
Also this:
http://www.gametrailers.com/video/gc-10 ... ium/705949From 1:46 onwards.
. I hope we get to see an Imperator in the game! 
