A few years back, Microsoft had special effects wizards WETA build a replica Warthog vehicle from the Halo universe. It was awesome, but with the ol' jalopy undergoing a subtle redesign for 343's new Halo games, I guess they needed a new one. So they had a new one built.
Aria Group, who makes replica cars for Hollywood movies, are responsible for this new real Warthog, which is almost 2.5m tall, more than 2.5m wide and more than 5m long, according to this story in the LA Times.
It's based on the chassis of a Hummer H1, has 49-inch tyres, and was commissioned to serve as marketing tool. If you think the exterior looks "realistic", it should; the modifications were based on 3D models of the vehicle sent over by Halo 4 developers 343 Industries.
I kinda like how the inside is so "plastic" as well. Looks more like the game came to life that way.
Halo's Warthog goes from pixels to reality [LA Times]