The Zhodani are the bad guys in the story, so they have to look mean. I've always liked the classic image from the early artwork but nobody makes a really suitable miniature.
These Japanese corporate troops from Ground Zero Games (GZG) are probably the best fit visually as they have similar ribbed effect on their armour but sadly the line is pretty limited in variety. I may still use them for second line or local units though.
My current top alternative are the New Israelis, again from GZG. These look more like Spartans from Halo than anything truly Traveller inspired but I think they look the part and the line has recently been expanded with several new packs, including heavy weapons.
For vehicles, GZG have again come up trumps, with a tank model that will nicely represent the Zhodani's Z-80 grav tank and a variant that will do nicely as an APC/IFV.