I am trying to achieve a similar effect to greeble. The problem with greeble is it destroys any mapping you have used before hand. Turning the object to a poly and then beveling all the independent polys achieves this effect correctly, keeping the correct mapping. BUT, by then changing to poly you destroy the previous modifiers and cannot adjust anything. Is there a modifier that will allow you to bevel all the polygons (independently) in an object?
After You select faces You want to Extrude/bevel on Your Poly and Before actually extruding/ beveling it change global pivoting from "one for all" to "one per each" and You schould have what you want - extruded?beveled faces independently.