nipx: Thank you vor the compliment. There is already a pipe texture. What kind of cable textures do you have in mind? Give me a good reference and I could add a last-minute texture to it.
What is does "hard surface" mean in this context? I did some tasks very similar as the author of this tutorial but I have to do some things a bit different in GIMP.

Inestical: Do you mean the normal map? This one can be created with a GIMP-plugin from a good grayscale height map. It took some time to find the best mix of depth and a good adjustment in the plugin but now I found my work-flow.
But sometimes I created the normal map in Lightwave and converted it later on in a grayscale height map. That depends on the object that I have in mind.