I thought about this problem and came up with the following solution. This is one side of the dust panel. I will cut a shallow tenon on the end of the runner and an accompanying mortise in the leg to accept it. This will capture the runner when I assemble the side panel. The runner will have a long dado in which the dust panel will ride (with a long tenon). I started cutting it up tonight. The Sketchup model has been modified and I think I have all the joinery worked out.
I completed both dust panel frames.
Here is the frame all cut up.
And the frame in the case.
It was much easier than I thought. Enjoyable too!
-- Scott - Chico California http://chicowoodnut.home.comcast.net