There doesn't look to be a way to bind to the mouse wheel.
The best way is to add them to favorites:
Favorite your stuff with F
Open the favorite menu with Q and assign numbers 1~8
ONE-HANDED WEAPON + SHIELD Combo : Press the corresponding hotkeys in any order.
ONE-HANDED WEAPON + SPELL : Equip the weapon first then the spell (you can then cycle through other spells and the weapon will stay in your right hand)
DUAL-WIELDING SPELLS : Simply press the corresponding hotkey twice. As far as I know, all spells can be dual-wielded.
As for dual-wielding weapons, there seems to be two methods.
Automatic Dual-Wield (SAME WEAPON ONLY) : With the favorites menu open, highlight the weapon you want to dual-wield (must have a [x] next to the name where x is the item quantity). Equip it as you normally would (we're not assigning a hotkey yet) THEN right-click. If done correctly it should now say "LR" next to the item's name. Now you can hotkey them !
Manual Dual-Wield : unfortunately, hotkeys don't seem to be supported with this but I'll post it anyway. Basically you'll want to open the Favorites menu, equip your right-hand weapon first with E (or whatever you have assigned to Activate) then highlight what will be your offhand weapon and right-click anywhere in the screen. Yeah it's kind of a pain as hotkeys clear the "L" but at least you don't have to click ON the weapon's name.
The above is from here
There's a video showing how here
This question has been answered here