Thanks, Cleo!! I think I can knock together one of these. Matter of fact I've got a super that came to me with the shelf hanger rabbet and the handle cut upside down on one of the sides that I can use for this. I'm using all 8-frame mediums so I'll have to cut the box down in size but it shouldn't be too big of an issue.
Thanks again for the pictures, they help me understand your design greatly!