There was one set of Paramilitary Goons with suitable heads, think I have them somewhere, just never finished them.
Left figure is as supplied (but assembled).
My first port of call is always Crooked Dice.
http://www.crooked-dice.co.uk/wp/product-tag/heads/Not quite what you describe, but Fighting Men (berets), Security Guards (Rounders caps), Balaclavas, Helmets.
I wish Empress would do some in their Universal Soldier range.