OK, it's submitted to HTC and also available at ah-skins.com.
thebest1, I this time I tried a pattern overlay of 'clouds' and then set its opacity low enough for a hint of it to show through, giving light and dark highlights to the base color I used.
Also I experimented with the materials.txt file, but that was more to minimize the problem with the black on the outer nacelle being more reflective than the black on the inner nacelles.
Just lots of playing around with different techniques and stuff.