Just wanted to share a little something I discovered yesterday: Jerry Kacey's White Lightning/Alien Bee adapter ring (http://www.kaceyenterprises.com/?page_id=481} works perfectly with folding softboxes allowing you to do this:
The icing on the cake is that it positions the flashtube fully within the box:
To make this work well with large, front-heavy folders like the QBox24 pictured, keep the lowermost lobe of the sofbox in front of the mounting ring while the other three lobes are behind it. The attachment is still very robust with the added benefit of the box being held in proper alignment with the light.
For the observant among you, yes, Jerry's adapter ring comes in basic black. I painted the front of mine white for another project.