The game mechanics only allow 2x5 skills to be slotted (when you have unlocked the 2nd weapon slot)
Theoretically you can change the 2nd weapon/skill slots while the first is selected, increasing your max slotted skills to any Nx5.
Wykkyds Outfitter does this.
http://www.esoui.com/downloads/info5...Outfitter.html
HOWEVER (as far as I know) the slots can't be modified while in combat, so you would have to decide for 2 of the N weapon/skill sets before entering the combat.