Grenadier, then West End Games, made metal minis for the old West End version of the Star Wars RPG. Obviously, they've been out of production for quite a while now, but you can still find them on eBay, etc. They made a fair number of PC-like minis, as well as a lot of soldier-types for both the Rebels and Empire.
I've used some Shadowrun minis (originally from Ral Partha; I think Iron Wind Metals is making them again) with some success, though many of them are fairly fantasy-esque.
Foundry has some modern / future lines that may be appropriate.
Some of the Iron Kingdoms / Full-Metal Fantasy minis might be appropriate, as well...I'm currently painting their Valeria Alvero mini for my wife's Soldier.
Metal ships are going to be difficult, if you want stuff that looks Star Wars-y. There is / was a sci-fi space combat game (originally came out in the late 70s/early 80s) called Starfleet Wars; the Federation fleet ships looked an awful lot like Imperial Star Destroyers. For ships in my game, I use a collection of plastic Micro Machines that I accumulated back in the '90s.
