That middle left helmet you started on really looks like it fits the bill already.
Don't forget ammo/gear pouches/harness!
Maybe one version without a gear harness, and one version with one
Well he might not add pouches and stuff necessarily (but then again I'm not alexscorpion). If he is going to emulate what he did in oblivion with his sneaking gear, then chances are he'll have addons like he did there and, I hope, a tactical vest. But the addons will perhaps consist of things like this. The night vision goggles in the front page look excellent. If he's going to make it better or even different, he'll do a lot more addons I imagine.
Knowing alexscorpions mods, this one will be amaing like the rest of them, and hopefully will include some sort of challenge to get the suit and addons, much like his sneaking gear in Oblivion.
Nevertheless, I'm eagerly anticipating this. Its on the top of my list besides the flying dutchman, FOOK V1.0, Nillacakesters classic mutants, and of course the FOIP compatibility patches for FOOK + FWE (I'm using the FWE+ FOOK merger now, but I want FOIP patch if they make one).
Well anyway, can't wait Alex. I've been looking places for a good helmet to go with the suit, but the other posters above me beat me to the mark. They all look fantastic for the suit.
EDIT: By the way, if you're looking still for some sort of helmet, there is one that you could base around. I'm not sure if it will be bulky for you or not, but I think it would look pretty cool with the suit.
http://fallout3nexus.com/downloads/file.php?id=9360
EDIT 2: Couldn't help but post this pic. The helmet here would also be another good base, perhaps. Unless you find it bulky of course!
http://fallout3nexus.com/downloads/images/5981-1-1254227208.jpg
Good luck with whatever you do, alex!