#484820: Initial D7UX admin header landed with a default set of shortcuts in a custom menu. The idea was that we'd allow admins to set up switching between different custom menus per user role, so that users in different roles will get shortcuts more relevant to their job (eg. moderators, content translators, etc. would get different shortcuts). User configurable shortcuts also came up. IMHO depending on what level of customization we need, this should either be implemented with a set of custom menus (if we have a small set of fixed shortcut sets) or some custom way, since setting up per-user custom menus would be pretty overkill (if per-user customization is deemed important).