After reading the report Strana posted for his minifig scale space battle against RoC and the Vol, I thought of a couple interesting ideas that might see use in a minifig scale space battle.
The Boarding Tank, a microsized tank designed to fit through the cramped spaces of a warship or building. It was inspired by someone (I forget who) saying that if they boarded the Vol cruiser, they would use a tank since it had a big hangar bay and fairly large rooms. The Boarding Tank carries a single flamethrower, so its offensive power is no greater than an ordinary trooper's, but its layer of defensive frontal armor makes it much harder to take down. I built this for combat inside buildings, but it's worth posting here.
Proof that it can fit through a 4 stud wide doorway. It's pretty much as mobile as a standard minifig.
A better version of this
from a NELUG game. This was my original inspiration.
One idea that I'm quite proud of is the ram drone. Basically it's a small robot ship that allocates all of its weapon capacity to a giant CC weapon. I envision these being deployed in squadrons of 10-20 from the launch bay of a small to medium sized warship. Each ram drone can (probably) destroy a small fighter in a single attack. They're like anti-fighter missiles, but reusable!
Now back to pining for a bunch of giant spaceships.