Because part of me is incorporated with the Classic-play RPG Blogosphere's mindshare programme, I will post my ad hoc combination a la Jeff's Alchemical post:
Rules-
Car Wars
ALBEDO
Chainmail
+
Setting-
Belter (Traveller sup.)
Advanced Trooper VOTOMS
Principalities of Glantri
=
Premise-
"Armoured Furries compete for Resources in System Space."
The above rules-sets are all d6 based, with the mechanics of each being 2d6 (if memory serves), perhaps making 'borrowing and blending' easier. Paul Kidd's Comparison Chart-based system featured in ALBEDO (and later, in Lace and Steel) is pretty darned nifty in my book, and would bring a great deal to the other two listed. Car Wars not only provides very detailed vehicle design and combat rules, but taken in full (Uncle Al's, Aeroduel, and Tank Wars) would more than flesh-out the ALBEDO rules for conducting atmospheric -- surface warfare. Chainmail would lend the wargameiness to massing personnel and materiel.
Advanced Trooper VOTOMS setting, while typical over-the-top anime schmalz, has an interesting world-by-world military milieu which could easily be condensed into a single large and delightfully unlikely star system, confining the action and travel-time-scale to a significant, but not overwhelming, backdrop for adventures. Belter, an old boxed Traveller sub-setting, unsurprisingly enough focused upon asteroid miners and their struggles for equality and/or autonomy while maintaining their grip on the economic ladder. Basic D&D's Gazeteer series, The Principalities of Glantry sub-setting is one of my fondest young-adult memories, and substituting space-based Houses for the noble-houses in that booklet, while treating the city and environs as the Homeworld and Inner Planets, ought to prove a winning combination.
All stitched together, radiant elements within asteroids are the primary mega-resource which power the spacefaring societies' technology, while the bare minerals of the rocks form the raw materials and locales for much of the action/conflict/exploration, given that (monstrous and) hostile alien life forms from a vanished epoch are dispersed throughout the home-system in old complexes and more recent bases.
Eliminating all of the standard PC races, and allowing only Anthropomorphics and traditional D&D monster-types to inhabit the same milieu ought to generate more complicated scenarios than simple 'Human/Demi-Human good-guys v. Humanoid/Monsters baddies'-conflict. No doubt that more technologically-developed, spacefaring Hyena Anthros meeting their throwback Gnoll cousins would be hard-pressed to utterly abandon (misguided) thoughts of 'uplift', while the Gnolls are only concerned with securing caseless battlerifles and the occasional hover FAV.
But... All of this will have to wait a potential lifetime for me to address in an actual RPG.
It was fun cooking it up, 'though.
