As in another Amazon integration extension, there should be a function that automatically searches amazon for products that are already listed from other sellers and provide the possibility to the owner to just be added as another seller to the already existing product listing instead of creating a new one. During the search, this function should present to the user possible matches for every product and ask him to choose the right one. The search filter should be chosen by the user (search by product name, UPC etc). This should be combined with the repricing idea.

If I have QOH of:

10 x SKU 1111a
12 x SKU 1345ba
15 x SKU 4562cc

I can set a buffer of 2 for the account, and Amazon will display:
8 x SKU 1111a
10 x SKU 1345ba
13 x SKU 4562cc

We sell mostly handmade / custom items, for which no UPC exists in the Amazon DB. For this purpose, Amazon has allowed us to create our own SKUs in their system. Can you please make sure that your new module will allow for automatic creation of SKU (if needed) when inserting an item into Amazon? Otherwise it will be useless for us, as we can't create 300+ SKUs in Amazon by hand...

The feature set and design for the Magento to eBay integration were well thought out. Integrating with Amazon should be the same..

One thing that you do not have on eBay is automatic repricing, I know of another Amazon extension that allows this and it would be a very powerful feature if you could achieve this. Basically you can enter the lowest you would be willing to sell something and the extension should always make your product slightly cheaper than any competition up to this point.