Not sure what problems you have with spriting, considering in your "lore archive" I saw some pictures, so you should be familiar with drawing at least on some level, so I'll do it step by step.
I guess you are using SketchUP? Are you familiar with rendering stuff and different normal/specular/AO/etc. maps(I am not really familiar with it)?
If Yes, it should be fairly easy to render decent templates of your ships and lay final touches in photoshop or gimp.
If No, you can try asking advice from kazi or maybe some other modders who are familiar with 3d modeling.
Next, if you will manage to render decent templates (and maybe some normal, specular, etc. maps - though I don't really know what will be usefull for finishing sprites) from your 3d models, and if you still have troubles turning them into sprites of good enough qaulity, you can try uploading these template materials, and maybe 3d models, here. Of course asking people in community to help is good way to do it too(you can even look up some names in this thread
http://fractalsoftworks.com/forum/index.php?topic=6264.0), but if you show us all the work you've done so far chances that someone willing to help appears are higher.
On a side note, while I can understand, and I think it is a good thing, that you have modeled your ships like a real 3d objects with details on every surface, in Starsector we are limited to top down view. So while creating interesting desings is a good thing, you have to think about these restrictions. No one will see cool stuff placed under and some stuff placed on the sides. And in the end you want players to be able to see cool stuff you came up with. I am not telling to desing completely onesided ships, but just try to make sure that in top down view ship's design is well-recognized.
Anyway, good luck with your mod.