The rate things are going, they may never make a Halo movie. So that short Neil Blomkamp put together last year may be as close as you get. And these shots of the Warthog used in that short may be as close as you get to it. Built by WETA, the guys behind the special effects for Lord of the Rings, it's crazy the amount of detail that went into a vehicle built not for a movie, or even a trailer, but a cheap concept pitch. Plenty of pics at the link below.
Close Up: Weta's Warthog (Part 1) [NZGamer]