My textures so far are a combination of the patterns available in Gimp (free Photoshop type software) and materials allocated from within Anim8or.
I'm going to try and improve then a bit but it's the sort of thing I could spend days working at for very little improvement.
Currently planning to make a smelter next that will take the ore from the mill and produce 'metal', whether I specify it as steel (or another metal) or simply a generic metal cargo I'm not sure about yet.
Hmm...how about the smelter producing Adamantium? LOL Then I could refit my XR2 and DGIV fleets to withstand all the abuse I put them through...