I am a fraud and a cheat Tobi.
These are mostly kitbashes--hopefully cleverly done so as not to get caught.
That's the center of the Deliverance Engine with a few touches added by carefully making the model around the textures.
One day I'll learn xsi--maybe in the retirement home.
Here are some more shots of others...
For example, the Gas Giant tankers I made for each faction are variations of the Phase and Tech Refinery ships and use their texture sheets and the Psi one is the texture for the Psi constructor--also using the model turned upside down and flipped end to end with a couple of hand crafted stylish additions I added that carry the textures well enough. These are all cruiser size ships.