Weird, I had gotten a handful of bodies in officer uniforms at about the same time I'd gotten a batch of Iron Core sets years ago, if they didn't come with the Iron Core stuff, I don't know where they came from. Maybe they were some leftovers from a 40K set that someone unloaded on a bitz site, otherwise they're a mystery to me now.
Truly, officers for an Evil Space Empire are something that could be souped up from any of the growing number of WWII or even WWI sets - it's more or less what the original Star Wars production did anyway with costumes, weapon props, and so on - used the originals for loose inspiraton, where they didn't use the originals for the actual props and weapons. As mentioned by others, Germans are the obvious choice, and the Panzer Lehr are probably the best option with the least resistance, but depending on how loosely you're willing to pastiche Star Wars, I certainly wouldn't rule out any of the other WWII or WWI factions as alternatives: a little black, dark grey, or red paint could go a long way toward making any officer models look like sci-fi villains.
Speaking of using historical figures in a sci-fi context, I wouldn't neglect the Wargames Atlantic Afghans, Boxers, or even Baron's War Peasant Levy as a source of bodies, heads, and other bits: they'd fit right into the context of a Dune or Tatooine. And, looking a bit outside the usual Star Wars box a bit, the Napoleonics and Romans would lend themselves nicely into a retro-scifi context (the WA "Citizens of Rome" set is basically the stuff of the classic sci-fi "Crystal Spires and Togas" aesthetic frequently seen in Star Trek, Ray Bradbury stories like "The Martian Chronicles", and comic books rooted in more or less the same era.... I don't think the frequently-teased WA Ancient Egyptian set has hit the shelves yet, but that sort of thing provided similar fuel with an Egyptian spin for the "Stargate" franchise.)
I'm glad to see more options available for power armor now - Reaper has plastic "Bones" figures that work nicely for this purpose (Blackstar Corsairs), but Wargames Atlantic has a couple nice options now - I rather like where the digital "Tentacus Armor" is going:
Still, we can absolutely use more aliens, robots, starfleet costumes, and proper space suits, and a little more love for post-apocalyptic sci-fi!
