Keybinds cannot be applied to a mousewheel. The Controls screen is simply scrolled whenever I try to bind a key to a mousewheel.

Possible fixes
While applying keybinds to a mousewheel would be useful, it would conflict with hotbar scrolling. A fix for this conflict is to create new keybinds for hotbar scrolling.

I am aware that scrolling is (almost) necessary for locating a specific keybind inside the Controls window. A fix for this is: once a keybind has been selected, take any input from the mousewheel and bind said keybind to the mousewheel input (up or down), essentially locking the mousewheel until a key has been bound.

Notes
I usually use MWHEELDOWN for jump (it's comfortable) input and using the numpad for "hotbar scrolling" (Counter-Strike anyone?).
A simple options.txt edit would not work because of the conflict with the hot bar.