Hi David,
Modeling would be the highest quality, if the modeling is done well of course ;o)
Bump Mapping will not give you this kind of effect, but it might help sometimes to support that, ... sometimes 9As would Normal mapping do, at least for the reflection)
If you like to use Sub-Polygon-Displacement (SPD), then use nothing less than 16bit/c. Any 8bit/c might not have the “steps” needed to get this done. Something like that as standard Displacement, I wouldn’t even bother to try, to be honest. (Edit: to just convert an 8bit/c to 16bit/c will change nothing, the gradients of the images need to be from the start in the 16bit/c quality. Other wise a little bit blur might help, but that is a trick. Tricks don’t sustain long enough for pro work./Edit)
Get a nice gray-map with a very high resolution of your displacement idea. You can reduce the size later on if needed. The gray-values will be responsible for the change, so the “graphic” must be excellent. The Polygon object should have a fairly good sub division to start from.
I know I speak very vague about the resolution and such, but that is not a simple number, as the final render resolution and how close the object comes to the camera will define the need for it, as well always a little bit over the max need, as changes will come.
All the best
Sassi