This question is kind of off-topic, are accessories like shoulderpads in hat allowed?
Graphics staff might know better than I would, but I would guess that in the future shoulder pads are probably going to be sold as accessories.
I think if you made a sort of helmet with shoulder pads that might be fine as just a hat. Then again, it may be better to separate it into two items if you were planning on submitting something like that for Christmas. Not 100% certain as I am not a part of the graphics team.