Mixable Potions

This is my alternative to stackable potions. Doing this would allow you to put multiple potion effects inside of 1 inventory slot. I was thinking of up to 4. This would be helpful in PvP because you could quickly put multiple potions on at the same time. Maybe this could use a special bottle that has to be crafted with a bunch of materials (e.g. Blaze rod, gunpowder, and glowstone)?