[rogue]

This sounds like an interesting project. I already have a API framework for X-cart that could be used for this by adding the order requests to it. Orders would be sent with an HTTP request to the API.

Another method is to allow each customer to send orders via FTP as a CSV file. Then a program would check his directory regularly to see if any order files are present. This would be simpler than a full fledged API if you did not already have the framework for one. Order files could be saved as required for proof of orders.

I'm not sure how to handle a custom payment process where one payment is made at the end of the day. With that scenario you would need to defer approval on each order, then at the end of the day "wrap up" all of a customer's orders with one payment. From my experience, it would be probably be best to charge the customer for each order. You don't want to send out a bunch of orders during the day only to find out that the customer did not have enough credit on his card to charge the order's total. By using the "normal" xcart payment methods, If the order credit card was not approved, then the order would be queued and not sent to final customer.

You would probably want a custom packing list that did not show your company name but your customer's name. Including how to contact the company, etc..