TeamXbox interviews Todd McFarlane, designer of new Halo toys and the Halo 3 controller. The first two pages are mostly about his failed baseball career and his entry into the world of comics, mainly Spawn, but by page three he's talking about how they make figures from the information Bungie sends them:

We're developing figures right now from the game that wouldn't necessarily be so loyal to the wireframe. We are actually treating the figures as if we were making a movie, and what the body positioning may look like in action sequences. There are some limitations to how the character can be posed in the game, so we are being a little more creative with the figures. We'll still use all of Bungie's data in terms of what the uniforms and armor looks like, but put the figures in a pose that is more military-like. In essence, more movie frame, and less like a screen capture from a video game.

McFarlane closes by saying there are Halo-related things they're doing that aren't yet public, so there's still more to come.