Hello,
Let me put a radical view to the packing material.
1) It should not be free, should be charged at say 25% or 50% of cost.
2) It should be orderable. 3 months are a lifetime in a sellers career. In one month a seller may have sales of 50 pcs, in next month he may sell 500 pcs and in the 3rd month 5000, that is the beauty of ebay. So ad packing material once in 3 months will not suit ever seller.
ebay can have listings of PS material live on the site where sellers can place orders in the quantity they need. This will also stop abuse of the material and better management.
ebaY need not keep stock of the materials themselves but could outsource it to any logistics company which would stock and ship the same. Many LSP provide this service.
------
Devesh