There are some nice textures on the Carrara content CD - there are some good metals in the TextureWorld set (such as the Stressed Metal lot). You'll see that the bump is simply a grayscale of the texture. Getting a texture to tile seemlessly is not too difficult in Photoshop - you use the Offset filter (under 'Other'). Suppose your picture is 128 pixels square. Then put 64 in the 'Horizontal' and 'Vertical' boxes. Make sure 'Wrap Around' is checked. Click 'OK' and the picture is divided down each middle into four bits and swapped around. All you need to do then is work over the joins with the clone (stamp) tool so that it looks good. Then you can test the tiling by selecting the whole pic, choosing 'Define Pattern' from the edit menu, then with a new (much larger) document Edit>Fill>Use:Pattern. If it looks good you can then use it as a map in C. Hope this helps.