-Traveller d20. Never really looked at it, but it might be a good fit for what I've got in mind.
It's fairly conceptually close to a no-force d20 Star Wars (not SWSE). (You'll find my name in the credits under Lead Playtesters, along with another roughly half dozen.)
If you want the game that was playtested, cut the prior service and adventure XP awards in half.
There are a number of bits that made it unpopular with d20 system fans...
Armor works entirely differently from most.
Armor results in doing two different counts of the rolled damages.
Criticals can kill even high level characters.
I like it, but not enough to run it again. I do, however, use parts ported to a hybrid edition.
It's version of the High Guard combat is VERY mechnically different from CT/MT/TNE/T4 combat... but very similar end results. The structure points mechanic is Dr Skull's tweak of either Hunter or MJD's base. And it works well.
Hunter's expanded version of the Bk 2 trade tables is a personal favorite.