Thanks guys.
Zardoz, the one with Sean Connery?
Saw it decades ago, so perhaps unconsciously.
Maybe I should have been clearer about some things.
The model does not have normals, so compute normal and texcoords from xyz won't have
any effect, I'm afraid.
The coloring is just one Power Fractal(world space) multiplied with a faint AO map
and an also faint cavity map (combined by a merge shader). Both maps are 4k, which
should be high res enough here.
Of course I agree that more PFs and, from my point of view a painted color map would
improve it. Tested some stuff, but it made it harder to see the smaller sculpted details
and those are what I wanted to be clearly visible in this case.