You're probably confusing Starbase components with modeling "extra" ship parts (with or without features that modify what effects they have on gameplay).
Sadly, the local library has been down since January here & I-Mod recent access is unstable enough that you won't be able to experience it before any gets fixed.
In X-Worlds 06-A, there are numerous components (Magnetic & Dimensional Jump engines, enhanced spying modules, etc) which are basicly an indirect tackling of TA editors (lacking documentations while i have yet again a rare opportunity to challenge staff & coders into "supplying" more complete modding solutions for their users, btw) but for Dark Avatar only.
3d-CADding is more of a external gimmick for creating a DirectX item for later use... AFAIC, only 3dStudioMax or Wings3d should provide a partially compatible basic mesh. But that's not the end of anybody's task since the GC2 format is complex enough to be almost exclusive to SD developpers (unless they share the Dummie points scale rating or the UV mapping "options", kinda technical but stilll necessary reference for proper independant designs) if only by the HardPoints or texturing schemas.
I made some, i don't see why anyone shouldn't be able to - also.
You might have troubles with Kryo to earn permissions, but if General Pants uploaded his great collection of Jewels here - everyone has the same rights too.