@lubos 
we are talking of a sales industry where there IS SURELY a timegap (weeks to months) between Order and Delivery and ALSO there IS SURELY partial delivery depending on stock and incoming stock.
So it is mandatory to have an order tracking facility for many good reasons
i endorse @lubos and dont suggest to have the item ledger more complicated with addition of per customer/sales order. instead i suggested to handle in sales order level only, please refer what i had expressed earlier in same topic above about how to handle/update the delivery item/qty. i am sure lubos can make it in much better logic.
Now, to present it
[quote=“lubos, post:15, topic:10650”]
The big question is how to present these features in the system in easily digestible way.
[/quote].
when we incorporate and have the order status field, then by search filter we will get the desired selection. ( completed / not completed). The ‘completed’ should disable copy_to delivery/invoice.
As per sales Order items(column), the partial delivered line_items will have line item status as ‘partial’ and ‘open’ for the line_items where no delivery at all.
Then, when the ‘uncompleted’ status order is selected and copied to invoice/delivery, it will bring only those items with ‘open’ and ‘partial’ status.
For Management Reporting and action, There should be a screen or report which will show all pending Orders with is total sales order value, partial deliverd value, invoice value, Not delivered Value.