I also can't rig, but that didn't really matter.
Here's the result of randomaly choosing stuff to put into a biped:

Legs are from a flood infected marine
Upper arms are from an elite (I don't know if they change color yet)
Left forearm is from a hunter
Right forearm / hand is a flood infection form
Head is the skull with a modified version of Jenkins' helmet on it (it says "Steve" on the back)
Torso is from a marine
other than that, it uses the MC animations. None of it is truely rigged, but rather each part is attached to the correct node. The custom biped bursts into flames when you turn on your flashlight.
Let me know what you think and if you for some weird reason want the tags, I'll post them later.