Kind of. You can set it so the controls change while holding a button, with the expression parser (right click the button in the controller config), but i don't think a toggle is possible.
For example, something like this:
(!`DInput/0/Keyboard Mouse:TAB` & `DInput/0/Keyboard Mouse:W`) | (`DInput/0/Keyboard Mouse:TAB` & `DInput/0/Keyboard Mouse:Cursor Y-`)
Will use W for up if tab is not pressed, otherwise Cursor up if it is.
You could then use outside software to then hold tab for you after pressing another key, to allow for a toggle.
For example, something like this:
(!`DInput/0/Keyboard Mouse:TAB` & `DInput/0/Keyboard Mouse:W`) | (`DInput/0/Keyboard Mouse:TAB` & `DInput/0/Keyboard Mouse:Cursor Y-`)
Will use W for up if tab is not pressed, otherwise Cursor up if it is.
You could then use outside software to then hold tab for you after pressing another key, to allow for a toggle.