Now...as far as your original, first question;
"Example:  Map a rugged terrain over a very large sphere or stone to simulate the surface of an astroid where a curved horizon is visible"

Yeah, that is the domain of the Displacment map. You could use a Terrain as a bump map in the Materials Lab, although that obviously will not look the same nor as good/realistic.

It's very unfortunate the Displacement system in Bryce is still so buggy, crash happy and only 8-bit.

The only workaround here would be to use a different program to permanently displace a mesh with a Terrain image, so that the geometry would actually retain that displacement and then import the mesh into Bryce for rendering. I've done this before with ZBrush. Perhaps the free Blender program can do this?

AS

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