Since it won't let me post on the issue itself, here I am presenting a more elaborate idea:

z -> takes you to a menu screen that defaults to spells
Z -> takes you to a menu screen that defaults to wands

(Optional: swap the defaults for non-spellcasters)

Now here's the tricky part:
when entering a menu with either of these keys, hit 'Z' again and it flips to the other menu, and effectively rebinds it to that.

Example:
I press 'z', I am a spellcaster so it takes me to spells, I press 'Z' and it becomes the wand screen. Unless I change it again, hitting 'z' from now on will take me to the wand screen, and it will remain defined that way for this character.

I'm not saying implement it in exactly this manner, but I think the general idea of on-the-fly customizability is worthy of keeping in the back of ones head and exploring further.

*EDIT

Maybe can be implemented in an even more abstract way--just have a 'menus screen' with tabs at the top for every single menu, and you can press a reserved key that rebinds the last-pressed-key to the currently locked on menu. (Could be perhaps be a bit too loosey-goosey in allowing you to screw up your preferred bindings???) Obviously next to each tab it would display what key currently takes you immediately to it. Also not having to back out is taken as given, here.