Hey you could help a lot of builders by letting the inventory go negative so they don't get their entire project shut down every time you run out of stock. Like maybe offer them a choice to pre-order if it's out of stock and then they can add it to their basket and pay for it and move on. I mean think about how long it takes to fill a shopping cart with all the items needed to build a cnc machine... then one of the items is out of stock... doh! I mean it's great that you're honest about your inventory and all but I don't mind getting 2 shipments where one comes a few weeks later as long as I can place my order and move on. An easy quick fix for this problem is to let the inventory go negative or tell the site to keep selling even after inventory is gone... then stick a note in the shipment that says some part is backordered and will be sent later. Then go back to the site when you get time and make it a pre-order deal like I described above.
I see both of the sides here. But I would add one more scenario. Take the case where someone orders something like The Dude here suggests and lets say its a couple motors that go into the negative. Now after the order is placed it is found that the part could no longer be sourced from anywhere for whatever reason. The builder (person ordering) is in a bad spot but so is the store. I think its unreasonable for the store to make this up but it is also unreasonable to have the customer think it was just delay until more came when at the end of the day the product no longer exists. Perhaps a middle road would be good and have a interest list or something where customers could sign up for something and be emailed when they are back in stock to actually do the order.
The cart we use at this time does not allow this. We are working on a new inventory software where we no longer need to add every thing one at a time to the cart it will be bundled together(thats the plan) and still be able to keep the single part inventory in time. Its going to take a little while to implement it but I think it will be a big help. We do apologize as we know its inconvenience for now and I wish we were able to integrate the store more into the site (looking into that as well) but for now this is the way we have to work it. It will get better in time