I actually already put together a fairly accurate "Spartan" look, using existing armor pieces.

Head: Master Chief Helmet
Torso:
- Green Wool Top
- Green Traveler Top
- Black GPD Vest
- Neutral Starter Army Vest
Bottom - Neutral Starter Army Pants
Feet - Neutral Starter Army Boots
Accessories:
- Nano-C (Phase Blade holstered - right) (optional)
- Green pompom gloves
Hand:
- Human Bazooka (optional)
- Ancient Katana (back mount)
- Assassin's Guise - Sniper Rifle (optional)
It's not exactly right, but it looks pretty close
ninja