I'm modifying the "Ask a question" Mod to let the customer request a sold out product to be restocked, check the example here:
http://www.konkito.com/index.php?mai...roducts_id=342

For now it only sends an email notifying the store owner, but I'm working on it to have it recored in the database and automatically notifies the customers when the products they want get restocked.

Tell me if you are interested in this Mod and I'll post it after finishing. Any suggestion is welcomed.