And this is the cognitive leap I had - that while it would be nice for there to be different results for any given table's version of the Imperial Terran consular government, there's not only no need for it to be delineated or generated in the same way as the Houses, it might be better for the game and the story your table tells if it's done in a totally different way! Instead of shoehorning the Terran faction into the same set of stats as the Houses, why don't we come up with some different model - something that still has room for variation from campaign to campaign, something that helps us come up with good stories for RPing OR interesting scenarios for wargaming. Maybe all we need for some nice variation on our Imperial Terran consulates is one stat! But what will that be?
To do this, maybe we should set some assumptions about the Terran role in the game. In the original boardgame, the Terrans have more and better units than any of the Houses, and have at least double the 'replacement points' of any single house as well. In two of the three scenarios of the original game, it's Terra and their hangers-on versus someone else (either the Rebel Houses in the main game, or the Silakka invaders and their hangers-on in the second scenario). Imperial Terra isn't here winning hearts and minds; in the introductory paragraph of the gamebook they're described in terms meant to evoke a sort of crumbling Roman Empire; perhaps here it'd be worth pointing out that the Terran 'leader' unit is Ward Serpentine, Imperial Consul and 'commander of the Berserkers of the Imperial Guard,' who are a stronger-than-usual Power Infantry Battalion.
So Terra is set up to be at least partially a military overlordship, having probably come to Antares 9 and imposed, at blaster point, their rule over the Colonial Houses (who no doubt came here Lord-knows-how-long ago and did the same thing to the poor natives) and I think their military and technological supremacy needs to be a constant. It can get whittled away during the game by the acts of the PCs (or by the results of continuous campaigning in a wargame setting), but for our start-state there's just no reason to roll for it. Similarly, while the Terran forces on the planet are probably cut off from the Empire as a whole (either actually cut off somehow, or just as a result of the weakening of the Empire overall), their high 'replacements' value means they've either got access to a logistical infrastructure of their own, or at least have pretty massive reserves of both materiel and personnel they can call on in the same timescale as the Houses' resupply efforts.
So what's interesting enough to make into a variable? How about we take a cue from Mr. Baker and jump the tracks entirely? Instead of rolling for firepower or industry, why not roll for the Imperial Terran attitude?
Granted, we've already established that Terra is probably doing a lot of (if not all of) their governing by the sword. But a Consulate that's wary of the colonials to the point of paranoia is going to generate very different stories from a Consulate that's nakedly contemptuous of them. A Ward Serpentine that expects (and may one day get) backup from the rest of the Empire will behave very differently from one who suspects (or knows for a fact) he's all on his own here on Antares 9, left behind by the receding tide of a dwindling Empire.
So maybe two stats, to give us a nice 4-box x/y graph. "Degree of Contempt" on one axis, and "Degree of Isolation" on the other? What would be other interesting variables along these lines? The book itself only ever mentions the Empire in terms of it's growing weakness - would it be better to assume that whatever's on the planet is all they've got and all they'll ever have, and come up with a different variable here?
EDIT TO ADD: The Silakka - the alien invader faction - are pretty powerful too, and cry out for some kind of behavior matrix of their own....