I think there are sci-fi games which attempt to give a similarly streamlined game, though I have not played Dragon rampant myself.. They may or may not have a similarly flexible generic force builder but most at least have a wide enough variety of statlines provided that you can use them to represent most anything.
A few that our club has used. The first three are free.
-Warpath 1.0. A fast way to get HUGE amounts of our old 40k forces on the table for ridiculous battles. No unit creation mechanic, but plenty of unit profiles provided. It's basically Kings of War in space.
The upcoming Warpath books are supposedly going to provide separate rules for platoon size skirmishes like the current 2.0 rules and the Company-and-above kinds of games that the 1.0 rules gave.
-WarEngine 2.1. Still available via the yahoo group for free. Good for platoon-or-so size battles. Not great for anything larger than light vehicles, but has an extremely flexible unit creation mechanic.
-In the Emperor's Name. Ostensibly a warband skirmish game in the 40k universe, but it's actually a great generic sci-fi game for 8-12 figs per side. Very fast and deadly.
-Blasters and Bulkheads. Uses the Goalsystem mechanics to create pulp sci-fi games in virtually any setting. Nice balance between heroic characters and bands of henchmen/mooks/fodder.
Other great rulesets with unit creation mechanics worth checking out would include Gruntz 15mm, FUBAR, Nuclear Renaissance (another set that is bigger than it's given setting).