Thanks @russ. Please can you vote for this thread? Comments are really useful (thank you), but they don’t “count as votes”, so voting is really important and I can see that you haven’t actually voted for this. You can find out more information on how to vote and generally how we manage feature requests.
You can view the outstanding invoices for any customer easily by going to the Customer then to the Orders, credit notes & payments tab, you’ll see a section labelled Unpaid orders.