Sounds all like good ideas and it's nice to see some brainstorming around this.

However, there are quite a few instances that has to be considered when and how articles are affecting the warehouse.
An example:A. When a customer order is set to be paid via invoice, the normal routine is to send the
merchandise and the invoice to the customer. Either separate or in the same package.
Today it seems VM is not able to handle this correctly. The article is still in stock,
since no payment has yet been made.
The administrator of VM has alternatively to reduce the stock manually or to hide the
article manually, if it was the last item. Otherwise another customer can place an order
that can't be managed. Actually multiple orders can be placed, if they too are made with
invoice as payment method.
Suggested solution: When a customer confirms the order and checks out correctly, the stock should be reduced.
Or at least some kind of status should be introduced that reduce the number of available
items in the front end. Making it impossible to buy already sold/delivered products.
Upon returned merchandise, the stock should be able to become increased with the number
of articles returned. Or the status flag removed/reset.
Some studies of commercial stock/warehouse/accounting software behaviour maybe could be of interest? I know there are differences between countries in how this is handled, but some kind of best practise ought to be possible to implement.
Regards
Akerman