Shield and Bow Upgrades

I think the ability to upgrade your shields and bows would be awesome.

We should be able to make different shields and bows that would allow them to be more durable than the ones we already can make. This could be done either by making the item from scratch or having some kind of 'upgrade item' that would go in a crafting table with your existing shield/bow to upgrade it. It would also be nice to have a couple of specific enchantments for shields, or at least allowing existing enchantments to work on them (like protection, blast protection, thorns, etc.).

I just think it would be useful to have different durabilities just like we have with swords and axes and stuff :)