I did a practice pack up of my XL Stumpjumper 29er today in preparation for British Columbia. The Jetpack by bikend fits my XL. I had to take the pressure out of front fork, my other option would be to take off the seat, which is more of a pain in the ass. Seems like a good case, my only worry is that is the bag ends up on its side and then something is smashed down on top of it. That would likely damage a wheel.
Here is a link to the bike case: http://www.competitivecyclist.com/biknd-jetpack