Do you mean an addon to ensure mail containing intricate items only shows up on your crafter? Or one to mail it from another character to your crafter?

If it's the second one then I doubt it's possible to create an addon to do it because you can't actually mail stuff to your own characters. The nearest you can get is mailing it to someone else (a trusted friend or your second account) and then have them reject the mail and you pick it up on your crafter. An addon couldn't automate that process because it involves two separate accounts.

But you should be able to do something similar using the bank (which is the intended way to share items between your characters). Try something like Inventory Manager or FCO Item Saver. I've not done it myself but I think it should be possible to set it up so your other characters automatically deposit those items into the bank when they open the menu and your crafter automatically picks them up.