Bob,
I had thought of it but as I'm 'just' the 3D guy and 'not' an architect my opinion doesn't carry much weight around here when it comes to design ideas.
But...... I do plan on putting my ideas on the table.
-
Replace the existing full depth floor with glass and lighting it from below but then I thought about how you would clean the covered area or replace the lights.
-
Have the risers of the steps in glass block with lights behind and either marble or timber as the goings/level areas, again maintenance would be a problem.
-
Marble risers with a new mosaic design for the goings/level areas, could be too fussy.
We'll see, its early days for this one but time's a ticking as a design will have to be resolved soon.