Cari: Thanks, it's just an idea at this point. I'm currently sitting on a couple extra cabinets too. It might be a fun concept to try, kind of like the universal treadle setups people have made. I want to be able to use every machine I own at some point-at least in theory-and it would be more convenient. I think I will start building my boxes to a standard size. Even if it doesn't go further than that, it'll simplify construction. We all have our favorites or go-to machines but I've also come to the conclusion that the only thing harder on a machine (not just sewing machines) than using it is letting it sit too long.
If you want to try one out I'd be happy to repair your cabinet and install a tray to set cases in for you.
Rodney