There is no direct alternative I could think of but there is a very helpful function which is usable in almost every application (except some Adobe products sic!). You can search through the menu options:
You can invoke this search field by pressing Command+Shift+/. This not only shows you where to find the menu entry but also possible shortcuts. You can still assign custom shortcuts for unbound and already bound entries with the Keyboard system preference pane. You can also press enter when an item is selected.