These are designs by Alistair Hughes for the KSP uniforms. The idea is simple, based around overalls, boots, a few accoutrements, at least for SAMBT.
To keep it simple, we discussed maybe a black pair of overalls, black singlet, with a utility belt, black boots (either black combat, or gumboots. Actually, maybe some yellow gummies would look good, at least for the tank crew.)
The external troops could have body armour, sort of like Starship Troopers, but without their god-awful helmets.
There are some easy touches to tart it all up, including high collars with a kowhaiwhai pattern, Southern Cross cross lapel or shoulder or chest badges.
Brass buttons down the front with a flap over the overall zips to make it look like a Hussar top? I’m pluckin’ here, that’s what I’m doing.
Note the Southern Cross insignia here with the full infantry uniform. Alas, what a sticky end some of them shall meet …
Now here, drawn with all the skill of a demented monkey with a biro stuck up its bunghole, was my initial sketch of how it could look. Yes, bloody awful springs to mind. But I’m the ideas guy. No matter how crap they are.
Kiwi Space Patrol 
combat gumboots will be awesome and working a costume around the overalls will make life cheaper and easy. the design around the collar is very nice. did that want to be embossed or just flat? fabric paint with some highlights could look good.