Hi mate, my texture really isnt worth having, plus its based on my models U.V's so will only really fit that, i only use very basic methods though, hope these easy tips help..in photoshop
pick a base color, add either lighter or darker stains, magic wand them from photos of concrete etc, keep it blended to the back ground, de saturate it and lower the opacity of its layer so it doesnt stand out too much, you now have a flat base color for your ship, but its got subtle variation in it.
Draw panels using line tool, when youve finished rasterize the layer, duplicate it and blur, the blurred version will be part of your dirt map, the crisp clean one will be your bump map.
Then just copy paste any interesting rust and stains you can find, i simply use the eraser to blend them in, de saturate and layer opacity etc.
free memory low..exception thrown