You know what we need?Some sort of addon, when you have a gun in your inventory and you pick up another gun, it turns into guns akimbo.Then if you have this enabled, if you pick up another one it becomes... well yeah.
I don't think that can be done without several datablocks for every possible combination.
For octokimbo you have to place all the guns in an octogon shape that resembles a minigun, except the handles all stick out wards and spin once in a circle and fire at the exact same time.