Allow for 'one of a kind' style business models

This is a rather general feature request. I'm interested to see if other drupal EC users would benefit from these from better support for this kind of business model. I'd also like to generate awareness of the issue and this area of E commerce that drupal EC is not currently catering for very well. I hope this thread will lead to patches being developed for EC to better cater for this type of business model...

A client of mine runs a store that parallel imports snow-sports product and sells only online in competition with physical sports-equipment stores.

Due to the industry's anti-internet-friendliness, he sources product overseas and doesn't have a continuous supply of product. He typically has 1 to 5 of each product, and cannot get more of exactly the same brand/model/size/color when they sell out.

Another client resells handpicked used clothing, and never has more than one of a particular product.

Both these situations require special stock management. The main problem is that drupal EC reduces stock by one when and only when a transaction is marked as paid. For one-of-a-kind style stores, this can cause a problem. It may take several days for a payment to be received and possibly a day or two more for the transaction to be updated in drupal EC (in a COD payment for example). During that time the product is still 'in stock' and others can purchase it.

The current solution I have for this is simply setting C.O.D such that transactions are marked as paid automatically, when the order is confirmed. However this is not ideal, as the order can not be marked as 'canceled' if the client doesn't follow through with the purchase. Additionally stock must be restored manually for each product the client purchased.

Would it be useful to calculate 'in_stock' based on 'stock' minus pending transactions? And then leave stock to be adjusted when the order is paid?

Or would it be best to adjust stock directly on order-confirm and order-cancel? If so, how can we avoid stock being adjusted twice on both order-confirm AND transaction-paid? Without disrupting inventory management for stores with large inventories and consistent supplies?

Another great feature for the second client would be to have a 'one-of-a-kind' product type where inventory is already enabled, and stock is one. Any exceptions to this could be done through a different product type.