The Chinese and who knows who else likely has all the engineering, either from buying it from Clinton/Gore or having it given to them by obama, if they haven't just taken it by any open door they might have found.
Given the fleet of F-16s around the world today and the retrofit/upgrade market potential well into the future, not to mention a few home grown look a likes, I bet the XL will fly again, one way or another.
The only chance an American F-16XL or any F-16 derivative will fly is if the JSF gets cancelled. Lockheed is unlikely to do anything that will remotely eat into the F-35’s market.
Yes, the cranked arrow, It still is an excellent design.