had an odd thought..a 'boomerang' method, because I don't have Photoshop (have Gimp, wonder if it could do this)
Create some random texture on a plain, look straight down. Turn off all the rendering 'balls'. Then start the render.As you know, you get a very pixilated render, followed by more refinement. When you get the density you like, stop the render and save the picture. Export, then import back in and use that as a heightfield..would it work?

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)