I think that is at least 2 separate systems. I think an phone order system where you can associate the order with any customer (as long as you are logged in through admin, the security should be fine—just don’t have access to saved credit cards if that’s every an option!), would be nice. In the shopping cart I use now, we have to reset the customer’s password—which sucks.
Invoicing the customer so that they can pay on their own would be a custom payment module I think.
Or I guess this could be one system: Basically if you place a “phone order” all you are doing is pre-loading a cart for the customer. Once finished, you e-mail the customer an “invoice” and they follow a link. Doing so kicks them straight to checkout with all the info filled in. All they have to do is select shipping and payment… It would be nice....
Maybe even a combination of the two systems? The option to either a) enter the payment info yourself (as admin) or b) email the invoice to the customer to complete.
That would be unique --- good idea Scott! :D