So, that gave me an idea, which I am not sure is possible with MW's engine.
1) on pre-made weapons/armor, we don't know what soul was used. It may be possible to randomly spawn a creature from lists that correspond to the enchantment charge of the weapon/armor.
2) a similar method could be done on user-made armor/weapons, although ideally:
3) it'd be best if the soul released matched the soul in the gem used to enchant the item.
Another possibility is to increase the danger by adding any souls from soulgems used to recharge an item. So, if you initially used a Bull Netch to enchant your item, then if it breaks, a Bull Netch will spawn and attack you. If you recharged your item with a Scrib, then if your item breaks, both the Scrib and Bull Netch might spawn to attack you.
Not 100% guarantee the souls will escape.
Discuss!
Also: I don't have any skills to accomplish this sort of mod. I'm just throwing the idea out here.