These look pretty good to me, they have some of that deco feel. The "wing" areas could be more defined, like the wings on the fighters. That might just be texturing though. Are you going to use the fighter textures?
I was planning on using at least similar textures to the fighters. The wings on the Guardian/Defender are mostly detailed through texture. If you look closely, then you can see the wings are flat, which is why I made them flat here.
Junes, look at that ship in your signature. It reminds me of the wings on that ship, with less detail of course...
As for the trade lane lore, why not have Ageira update the entire Sirius trade lane tech, which gets them HUGE income from the houses to upgrade it all. Toss in a little extra for the lanes to be themed for each house and they get a bit more money.
Does anyone have any recommendations for the center hub? It's probably going to get more or less completely redesigned, so any ideas or feedback would be very helpful.