FASA Games, Inc.

I'm sure there is a sourcebook I'm missing, but I cannot find any material detailing vehicles, force compositions, or even general tech levels of ground forces in the Fadings Suns universe.

Can someone point me to the proper material?

Nope, such a supplement has never been published. FS belongs (or used to belong) to the WoD era of games which focused little on nitty-gritty details to the advantage of drama. The closest thing there is, would be the Legions of the Empire sourcebook which discuss warfare in the Known Worlds at some length, although it focused on backstory and drama rather than war gear and bits.

So nothing to draw vehicle specs from?

I was wondering why I could never find them over the years.

There's the odd vehicle scattered throughout FS sources, with Legions of the Empire having more than most. The FSR Players Guide has the biggest collection, although these are generally non-war vehicles and even that list is by no means extensive.

I would love to do old school sourebooks for vehicles, starships, and general stuff at some point, you know, the kind of books that games like Twiligh 2000 and Cyberpunk had. When we get to tackle Noble Armade, I am sure starship sourcebooks will become a requirement. But we're a small team (at the moment), so were not quite there yet

As soon as I've compiled them and alpha tested them, I will absolutely post them. I've already got some ideas for force composition and construction theory for the various houses, the Muster, and the Church. As I get more and more worked out I'll post it.