I know what you are saying and what you want, because I'm trying to do the same thing!

I want to run report of all the expenses that were entered into QB for the month.  That report has a column that says 'billable,' and beside each expense it says 'yes,' or 'no.'  

And there is also a column that says customer.

There is a report just like this for employee time.  But we definitely need this for all expenses.  It's not about seeing which billable expenses have not yet been billed, but maybe I forgot to click the 'bill to client' button and now I will never know about it!  If I could run a report and see something that I know should have been billed to a client but it says 'no,' in the billable column then I know I made a mistake and can fix it!!!