I wanted to show briefly the kind of thing you'll be able to do with multiple items in the same slot in the upcoming Warrior Mini (and eventually HM3):
What you see are four separate Headgear items stacked and moved on top of each other. The tank-goggles on the helmet are separate from the WWII helmet are separate from the cool modern shades are separate from the mouth mask. I think this is going to make some really awesome effects possible. I was up late last night thinking of all the possibilities once you bring various Insignia into the mix, too -- imagine building your own custom logo from basic shapes layered and sized, with pre-drawn icons to go with them. Or you could take a simple triangle logo shape and mask it to the helmet, to get a chevron effect on the headgear.
The more items I add to this thing in more slots the more excited I get to really explore the possibilities.