We use an Audit Rule that detects when trips are not booked with Concur - the user has to add a comment but can still submit - and we use the standard report under Compliance for Expense Exception Analysis. The "Travel" and "TripLink" reports tend to not have all the data for our configuration, so we base it on the audit rule. But, if you want a travel report, I would be interested to see what others use for this.
@jasong1989 There is an audit rule called No Matching Travel Reservation. Give this a look and see if it will help you. It is specifically for Airfare, Car Rental and Hotel expense types. If any of these are entered on an expense report and not associated to a booking done in Concur, it will flag the line item with a red exception. You can change the exception level if need be, in case you only want these items flagged with the yellow warning. If you notice the Exception code for this rule it is TRVRES. I mention this because in Cognos reporting, you can build a report that shows expenses that have this Exception code.
I hope this helps.