To quote them :

"Q : Your fans have been waiting a long time for a DVD. What about this project?
Justin : We thought about that, but we were distracted by our desire to make a new album. We think it could be something nice, but we're not the kind of band to do things by halves, so this project is going to wait. The new album and the tour are our priorities."

They don't say they won't make one, they say it's not in the plans right now.