The Spartan III/Mark IV and V didn't focus on whole armor (heck the differing Helmets in Halo Wars only had shoulder/helmet differences...), except some supplementary attachments clearly match up to standards of primary variations.
Helmet: EOD
Torso: Base Security
Shoulders: Base Security
Legs: Grenadier
Tada, classic EOD
On my comment about Spartan IV armor prototypes, most, if not quite a few are still prototypes, but don't behave according. Technology slapped the face of science and out of the blue Mark VII is possible.