Great, we'll it seems that this easy modification has worked with you all. I've found the best mini-fig heads that I like for this are the sharp toothed cannibal like head, or something alien looking. I'll show you here...
See, some seriously sinister super soldiers (alliteration for Blitzen).
I wanted to try J+B's shoulder armour and it looks quite effective and doesn't get in the way.
The added height doesn't seem to look odd either. Thanks J+B.
Another idea for using the fireman rebreather part is with this type of torso armour. It somehow handily clips into the back quite neatly making a fairly nice alien style armour.
As before the height isn't too bad either. Hope you like and as always feel free to use any of this.