Can you add a menu item to the poser.xrc file if it doesn't already appear there ? I would like to add Copy Material, Paste Material & Apply material to all and then add keyboard shortcuts for them.

Yes, you can. 

It works nicely, IF the command is already a main menu item.  I don't know if actions inside the material room would work that way.

If not, you can use another trick inside the ScriptsMenu folder.  Find or write a python script that forms the action you want, then give the script a filename that includes the hotkey.

For instance, I have a SnapTo script that I've rigged to act on Alt-Z.

The script is in the ScriptsMenu folder, and its filename is

SnapTo###Alt+Z.py

Taking this apart:

The title SnapTo

 then ###

then Alt+Z

then .py

Thanks, ockham. I have no scripting skills, although I did manage to create a shortcut for duplicate.