Not originally saying anything was taken directly from Homeworld, but I was thinking more along the lines of influence. For example, take the vertical model and flip it on its side, comparing the geometry to that of the Vaygr Battlecruiser. I'm sure you can see some parallels in the overall shape, though the details, function, etc. are different. And the vertical flight is far from original with Homeworld (see Boba Fett's ship in Star Wars), but the Mothership from the first game probably echoes in the minds of modern gamers when they see something that also flies vertically.
All that not withstanding, you've created a model that achieves your two largest goals. The first is to make it low poly while still looking good. The second is to practice your texturing, especially where it can artificially enhance the low poly design to fool the eye. Well done.