Format Painter in Microsoft Office
The answer is to use Ctrl+Shift+C to Copy Format and Ctrl+Shift+V to Paste Format.
The official Office-wide Format Painter key combination is
Alt+h+f+p
This is awkward to press, though, especially when standing up.
So I automated this with an Autohotkey script:
^Numpad0::
Send, {ALTDOWN}hfp{ALTUP}
return